An historical collection of more than one hundred samples of minerals and ore, used in the second half of the XVIII century was found and acquired during Munich Mineralientage 2014. The samples contained in numbered glass vials but lacking description, were prepared for teaching purpose about determinative mineralogy and ore recognition. All samples were analysed and identified. The identification effort drove the authors along a historical excursus about the didactics of mineralogy and the dry method analysis, nowadays neglected.
During the 2014 edition of the most important European mineralogical exhibition-held in Munich every year― one of the authors, collector of mineralogical memorabilia, bought 19th century wooden box containing the 102 samples analysed in this study. The main objective of the acquisition and therefore of the present investigation has been the identification of each sample contained in its corresponding glass tube, as no historical list or label is anymore existing even if very probably it is, either for analytical or didactical purpose
A didactical collection of old samples has been rarely analysed with modern methods and instrumentations
and the results are of particular interest because they show what kind of mineral and substances are considered as industrial and scientific relevance at that time.
During the development of the industrial mineralogy, in the period starting from the late ‘700 to the beginning of the ‘900, there was a strong need for chemists and geologists of easy, quick and reliable analytical methods. Their essential requirement was to guarantee an analytical accuracy in determining the presence of major or relevant elements in a mineral or in an ore rock, so that the industrial exploitation could be justified.
The classical analysis through dissolution, precipitation and weighing, although already well established at the middle of ‘800 (at least for the most important elements) was a long, annoying and time consuming way to obtain chemical information about the composition of a generic mineralogical sample or of a specific ore sample, that is a mineral or an aggregate of minerals from which a valuable constituent, especially a metal, can be profitably mined or extracted. It needed a well-equipped laboratory, a number of chemical substances and a skilled chemist. All these conditions collided with the needs of obtaining, directly during the field search and in a short time, the information needed to prepare suitably the mining work and focus the research on the different field areas.
In order to satisfy the above request, different methods of analysis, which require no or little chemical manipulations, a minimal use of chemicals and laboratory tools, and only a simple training were developed. The most of them are practically using no water or acid for dissolution (and consequently no or very little glassware, as it is always problematic to be used in the field) and for this reason are called dry analysis methods. Essentially, these methods consist in observing the eventual modifications, reactions and transformations of the sample once heated, melted with simple chemicals, or placed in a flame.
The main methods are listed as follows:
-Heating on a platinum foil: the analyst could observe combustion (organic substance), possible formation of residual deposits, developing of volatile substances (some of them recognizable by their smell), fusion or resistance to heat. All of these characteristics could orient the researcher to different ways.
-Heating in close test tube: the observation of a small amount of unknown ore or mineral placed in a small test tube, heated on the base, can give useful information about the presence of water (condensation of droplets in the cold zone of the tube), sulphides (condensation of sulphur or developing of SO2 or H2S) and so on. The release of carbon monoxide―burning with blue flame at the top of the tube―can reveal the presence of formiate or oxalate groups. The release of red vapour of nitrous oxide suggests the presence of nitrates, whereas the ammonia smell suggests the presence of ammonia salts or nitrogen bearing organic substances.
Different sublimates can be deposited near the edge of the tube, such as red mercuric sulphide, or orange arsenic sulphide, thereby suggesting the presence of such so important industrial elements like mercury or arsenic.
-Heating in an open test tube: a small test tube, shaped as wide opened “U” arms, with a small amount of the sample placed in the lower part of the tube, is heated in a flame. Differently than the previous test, the air flowing in the tube from the open side can produce an oxidation of the unknown mineral developing different substances compared with those of the previous method.
-Heating on coal: a small amount of the substance, placed in a small pit carved in a coal brick, is heated directly by blowing the dart of a flame on it. The reaction with the coal can release small droplets or globules of reduced metals, such as lead, tin, zinc, bismuth, but also, in some cases, gold and silver, in revealing the interest for a mineral exploitation. Aside of these fortunate events, also the developing of a white or coloured halo on the coal can suggest the presence of some metals, and the variation of this method (heating in an oxidative or reductive flame and mixing with sodium carbonate) gives a lot of information to the chemist. In adopting such a method it would be very useful the use of an instrument called blowpipe.
-Flame test: this well know test even nowadays is based on the coloration assumed by the flame of a alcohol lamp (or better, if available on the field, a Bunsen lamp) which would reveal the presence of many different metals like copper, lithium, barium, potassium and so on. A skilled chemist can also notice the different colour obtained by using the substance as it is, or wetted with hydrochloric or nitric acid.
-Borate and phosphate pearls: this method also practiced by modern chemists, consists in obtaining a coloration in a vitreous mass of sodium borate or sodium ammonium phosphate (phosphate salt); it is a useful tool to suggest the presence of some metals in a substance. A small amount, sometimes a single grain of unknown substance is mixed with sodium borate (or phosphate salt), and heated until fusion. The developed colour, the difference of colour between the hot and the cold pearl, the tinge difference in oxidative or reductive flame are the distinctive features that could drive a chemist to the identify a specific metal in a mineral.
These are only the most important ways to test a substance without (or reducing to a very minimal amount) the use of acid, base and chemicals. Almost all these methods drive only to the identification of the metallic or semi-metallic element contained in an ore, because metals were (and still are) the base of the modern industry, and except in rare occasions, no relevance must be given to the oxidation state and/or to the coordination number of the metal within the crystal lattice. For example, there is no reason to know if chromium is in its trivalent or hexavalent form, or if copper carbonate is azurite or malachite. However, even if these methods of analysis look like quite simple, a training of the chemist or mineralogist is necessary. This is the reason why in the past many analytical kits producers organized didactical collections, containing samples of the most commons minerals, particularly interesting for the industrial exploitations.
In the modern day education of mineralogists and chemists, the study of blowpipe analysis becomes only a historical curiosity. On the other hand, by using this technique from the end of the 18th century to the middle of the 19th century, the qualitative composition of most minerals was identified and contributed to the discovery of over 15 elements [
In 1862, the German mineralogist Franz von Kobell (1803-1882) described the blowpipe as an instrument that “in its way, served chemical mineralogy as much as the goniometer served crystallography” [
The reaction in the oxidizing or reducing zone of the flame can be easily observed with charcoal, clay, glass or platinum serving as a support. The sample, submitted to various tests with the blowpipe, can be analysed with the addition of fluxes and reagents. Most metals can be identified through the coloration of the flame. Much experience and talent is necessary for an efficient work with the blowpipe. Complicated modifications to the original blowpipe design were applied sometimes even including the use of oxygen or hydrogen to obtain the highest temperatures. The origin of the blowpipe is lost in antiquity but was probably an invention of the Egyptians whose goldsmiths were familiar with the use of metallic blowpipes as shown on wall tomb paintings dated around 2400 B.C. However, the very first description of a blowpipe experiment conducted on a fossil sample is due to the English physicist Robert Hooke (1635-1703). The Danish physician Erasmus Bartholin (1625-1698), in his famous work of 1669, not only was the first to recognize the crystal optics but was also the first to perform experiments in the field of crystal chemistry by decomposing a crystal of Iceland spar into lime by means of a blowpipe [
Particularly in Sweden the blowpipe was used by mineralogists and metallurgists for quick qualitative tests of ores, while in Germany at a later period, a school of blowpipe technique gradually evolved so that the teachers passed on their knowledge to their assistants. Among them, Andreas von Swab was the first to start using constantly the blowpipe for mineral analysis about the year 1738 [
rived from Greek meaning to effervesce. In 1770, Gustav von Engestrom (1738-1813) published very clear and illustrated instructions for the use of the blowpipe. This talented chemist invented not only a blowpipe, but also various other items for blowpipe experiments which all fit into a neat, small box which could comfortably be carried in a pocket―especially on travels―so that it could be called a pocket laboratory [
The Swedish chemical genius Torbern Olof Bergman (1735-1784) published many articles and treatises mentioning blowpipe experiments in passing. These were not limited to minerals but also extended into the fields of mineral waters and organic matter. In his main work of 1779, a modified 3-piece blowpipe made out of silver was described. In addition to charcoal, he also used a silver or gold spoon as a sample support; his portable kit also included an anvil, a hammer, some specimen pliers and a candle holder [
Bergman’s most important student was Johann Gottlieb Gahn (1745-1818), who became his assistant at the chemical institute of Uppsala after 1767. Later he built his own laboratory in the mining town of Falun and became an unsurpassed master in the art of blowpipe analysis.
Jons Jakob Berzelius (1779-1848) was probably the most famous of the Swedish chemists. In 1803, he discovered cerium and later thorium and selenium (Bergman, 1779). Even if at his times he became famous for the blowpipe technique, he is the inventor of the chemical symbols in common use today and he proved the law of constant proportions. Also thanks to the invention of many types of laboratory equipment, he transformed the alchemical cellar into a modern laboratory. Among the many innovations, Berzelius introduced the practise of the analytical separation by using hydrogen sulphide to precipitate metallic sulphides, later on tested by means of the blowpipe. In his classic book of 1821, all aspects of the blowpipe analysis were clearly summarized and several different types of blowpipes as well as a special oil lamp designed by him are described in detail. In such a way, he was able to distinguish the four zones of the flame and used the key-words oxidation and reduction in this context [
Later on Edward Turner (1798-1837), a chemist, was one of the first to use the coloration of the flame as a diagnostic mean. He developed a technology to prove the existence of lithium in hardly fusible mineral species [
The “Pope” of the blowpipe analysis was the German chemist Karl Friedrich Plattner (1800-1858) who studied in the Mining Academy of Freiberg and invented new procedures for quantitative blowpipe analysis for gold, copper, lead, tin and (at a later stage) for nickel, cobalt and bismuth [
In 1837, the above-mentioned Franz von Kobell proposed―in analogy to the well-known Mohs’ hardness scale―a six-step fusibility scale and demonstrated how close-looking the mineral species could be differentiated by its application: he suggested that samples of the minerals in this scale should always be kept handy for comparative purposes.
The decline of the blowpipe began with the invention of gas burner by Robert Wilhelm Bunsen (1811-1899). Such an equipment was able to reach temperatures of more than 2300˚C and the research focused on the experiments with the indicative coloration that molten substances imparted to the flame [
The 1912 discovery by Max von Laue (1879-1957) of diffraction of the X-rays passing through a crystal established the possibility of relating crystal structure to the chemical composition of a mineral. This new, revolutionary method delivered the end to the use of the blowpipe, which had played such an important role during the century from ca. 1760 to 1860.
A multidisciplinary approach has been focused on studying the old samples. First, an elementary analysis has been accomplished by using a SEM-EDS, in order to identify the main constituents of the mineral phases. Subsequently, a XRPD identification has been carried out, by reducing the compositional range of the suitable mineral phases to what suggested by EDS.
The first check has been done by means of a SEM Stereoscan 360 (Cambridge Instrument), coupled with an EDS Link Pentafet (Oxford Instrument) equipped with a “thin window” detector, allowing qualitative/quantita- tive chemical analysis of light elements (down to carbon). Working parameters are as follows: acceleration voltage 15 kV, working distance 25 mm, probe current 1 nA and spectra acquisition time varying from 60 to 300 s. Daily standardization has been performed by using a pure Co specimen. Chemical data have been collected on coated carbon fragments of the samples, processed with the Inca 200 Microanalysis Suite Software, version 4.08 with main calibration on natural mineral standards by using the ZAF correction method. The instrument could not recognize hydrogen, lithium, beryllium and boron, therefore the presence of these elements has been often supposed during the following analytical step. The analysis, normally performed on unpolished samples, has been considered only as semi-quantitative and approximate.
XRPD characterization has been carried out on crushed sample using a Panalytical X’Pert PRO (Cu Ka radiation) diffractometer, with a PIXcel detector, a solid-state detector with rapid readout time and high dynamic range. Data collection has been performed between 5˚ and 90˚ 2q, with a step of 0.02˚ 2q. ICDD-PDF database has been used to interpret powder diffraction patterns.
The main goal (the identification of the mineral species contained in the historical wooden box) has been achieved with a high degree of confidence. Most identified minerals were interesting for industrial or technological purpose, as it can happen to a collection assembled on the behalf of teachers of quick mineralogical analysis and practical application.
A certain order in the distribution of the samples has been noticed: with some exception, the original sequence of numbers labelled on the tubes follows a chemical periodic order. At the beginning there are the mineralogical species containing cations of the first group (Li, Na, K and even ammonium). Then there are the samples containing the second group elements (Be, Mg, Ca, Sr and Ba). Afterwards, there is a group containing the most common transition metals (Mn, Zn, Fe, Ni, Co, Pb, Cr, Sn, Cu and Ag) in many cases as carbonate, oxide, sulphide, arsenide or antimonide, rarely as native element (like silver and arsenic,
Uranium and REE belong to this group as well. The next group includes partly mixed and strictly correlated rarer species containing unusual or less useful―for that epoch!―elements (niobium, titanium, tungsten and molybdenum). The series of samples, besides some common silicates, finish with some organic substances as beeswax and amber, probably used to show the reactions of organics under the dry analysis (to be noticed the choice of the former, very fusible, and the latter almost infusible), and of a very fusible inorganic material (boric acid).
The last sample is quartz, one of the best examples of simple mineral without perceivable cations, and almost impossible to melt. On the opposite, the diffractometric technique allows a certain identification of each phase (
It is remarkable to notice that many of the samples are real ore fragments, containing different silicates as mother rocks or containing two or even three different species of the same cation, as it could be expected to be found during the normal field activity. The analytical work on the samples of the present study have allowed to identify the mineralogical species which were strategic from the industrial point of view of the time and interesting for representing the chemical reference terms. All the samples have been surely identified (
# | Description at glance | SEM-EDS analysis | XRPD-analysis | Identification and notes |
---|---|---|---|---|
1 | White crystalline powder | Oxygen, sulfur, aluminum and nitrogen | Ammonium aluminum sulfate hydrate ICDD PDF 83-1933 | Ammonium aluminum sulfate, dodecahydrate (NH4)Al(SO4)2・12H2O The material, apparently synthetic, belongs to the collection probably to show the reactions of a very hydrate and heat-reacting substance |
2 | White crystalline powder, traces of natural plane faces and “cubic” aspect | Potassium and chlorine | Sylvite ICDD PDF 41-1476 | Sylvite, KCl Could be either of natural or synthetic origin |
3 | White crystalline powder, no traces of cleavage | Silicon, potassium, aluminum and oxygen | Potassium feldspar (Adularia) ICDD PDF 71-1543 | Adularia, KAlSi3O8 |
4 | White crystalline powder, traces of cleavage and/or flat faces | Calcium, silicon, oxygen, fluorine, minor sodium and iron | Fluorapophillite ICDD PDF 71-1778 | Fluorapophillite KCa4(Si4O10)2(F0.5OH0.5) (H2O)8 |
5 | White smooth powder | Oxygen, sulfur, sodium, potassium, calcium | Sodium nitrate ICDD PDF 89-2828 sodium potassium sulfate ICDD PDF 74-0394 | Mixing of laboratory chemicals, mainly potassium nitrate (KNO3) and sodium potassium sulfate (KNaSO4) Probably synthetic, could have been included to show the reaction of nitrates and sulfates of alkali elements. |
6 | White granules | Fluorine, sodium and aluminum | Cryolite ICDD PDF 25-0772 | Cryolite, Na3AlF6 |
7 | White crystalline fragments | Oxygen, silicon, aluminum, sodium and minor amount of potassium | Albite ICDD PDF 89-6423 | Albite, NaAlSi3O8 A plagioclase very close to albite composition |
8 | White crystalline fragments | Oxygen, silicon, aluminum, calcium, sodium and minor potassium | Albite ICDD PDF 89-1939 | Albite, NaAlSi3O8 A plagioclase in the range of the albite-oligoclase composition |
9 | White crystalline powder | Oxygen, aluminum, sodium, silicon, small amount of calcium | Natrolite ICDD PDF 45-1413 | Natrolite, Na2Al2Si3O10・2H2O |
10 | Missing sample | |||
11 | White powder | Oxygen, sodium and minor amount of magnesium, sulfur and chlorine | Tincalconite ICDD PDF 07-0277 | Borax or tincalconite Na2(B4O5(OH)4) (H2O)2.668 It was probably Borax, but the long time altered it in a derivative of borax, Tincalconite. |
12 | Pale yellow crystalline powder, some fragments with cleavage | Oxygen, phosphor, iron and manganese | Lithiophilite ICDD PDF 13-0336 | Triphylite, Li(Mn,Fe)PO4 A sample of the Lithiofilite (Mn) and Triphylite (Fe) series, close to the Triphylite because of the iron content. |
13 | Pale whitish-yellowish fragments | Aluminum, silicon, oxygen | Spodumene ICDD PDF 71-1063 | Spodumene, LiAlSi2O6 |
14 | Withe powder | Aluminum, silicon, oxygen | Petalite ICDD PDF 35-0463 | Petalite, LiAlSi4O10 |
15 | White powder | Aluminum, silicon, iron, manganese, potassium and fluorine | Muscovite (fluor-muscovite) and/or celadonite ICDD PDF 49-1840 | Muscovite-Phlogopite series |
16 | White crystalline powder | Aluminum, silicon, oxygen, manganese | Lithiophorite ICDD PDF 41-1371 | Lithiophorite, (Al,Li)MnO2(OH)2 A mixture of Lithiophorite and Quartz |
17 | Greenish-blackish fragments | Oxygen, magnesium, silicon, calcium, iron and lesser amount of aluminum and chromium | Magnesium-hornblende ICDD PDF 20-0481 | Magnesio-hornblende (Ca,Na )2 -(Mg,Fe,Al)5(Si,Al)8O22(OH)2 |
18 | White crystalline powder | Carbon, oxygen, barium | Witherite ICDD PDF 71-2394 | Witherite, BaCO3 |
---|---|---|---|---|
19 | White crystalline powder | Carbon, oxygen, barium, calcium | Cobaltocalcite ICDD PDF 15-0285 | Baritocalcite, BaCa(CO3)2 |
20 | White crystalline powder | Strontium, oxygen, sulfur | Celestine ICDD PDF 05-0593 | Celestine, SrSO4 |
21 | White crystalline powder | Strontium, oxygen, carbon | Strontianite ICDD PDF 71-2393 | Strontianite, SrCO3 |
22 | White crystalline powder with traces of cleavage | Fluorine and calcium | Fluorite ICDD PDF 70-1469 | Fluorite, CaF2 |
23 | White fine powder | Calcium, oxygen and sulfur | Gypsum ICDD PDF 70-1469 | Gypsum, CaSO4・2H2O |
24 | Glassy yellowish and bluish fragments, conchoidal fracture | Phosphor, oxygen, calcium, fluorine, a small amount of chlorine | Fluoroapatite ICDD PDF 71-0880 | Fluorapatite, Ca5(PO4)3F |
25 | Missing sample | |||
26 | White crystalline powder | Calcium, carbon, oxygen with minor amount of magnesium | Calcite ICDD PDF 89-1304 | Calcite, CaCO3 Composition is very close to pure calcite, with only 0.03% m/m of magnesium |
27 | White crystalline fragments | Silicon, calcium and oxygen, with minor iron and chromium | Wollastonite ICDD PDF 42-0547 | Wollastonite, CaSiO3 |
28 | Green crystalline fragments | Silicon, calcium, aluminum, iron and oxygen, with minor amount of sodium | Clinozoisite ICDD PDF 71-1539 | Epidote, Ca2(Fe,Al)3(SiO4)3(OH) The sample is a mixed member of the series Clinozoisite-Epidote |
29 | White greenish scales | Magnesium, silicon, oxygen and minor iron | Talc ICDD PDF 29-1493 | Talc, Mg3Si4O10(OH)2 |
30 | Missing sample | |||
31 | Creamy-white powder | Calcium, carbon, oxygen and little amount of iron and manganese | Ferroan Dolomite ICDD PDF 41-0586 | Ferroan Dolomite, Ca(Fe,Mg,Mn)(CO3)2 Magnesium in dolomite is often replaced by a small amount of iron and manganese |
32 | Whitish powder | Carbon and oxygen | Phenolphthalein ICDD PDF 51-2358 | Phenolphthalein, C20H14O4 Phenolphthalein is an organic pH-indicator that does not match with minerals. Probably it was used as a replacement of a consumed sample |
33 | White powder | Manganese, sulfur, oxygen | Manganese sulfate hydrate ICDD PDF 33-0906 | Manganese sulfate monohydrate MnSO4・H2O May be a laboratory product |
34 | White powder | Sodium, sulfur, magnesium, oxygen | Magnesium sulfate hydrate and sodium magnesium sulfate hydrate ICDD PDF 72-1068 ICDD PDF 71-0307 | Magnesium sulfate hydrate MgSO4・6H2O Sodium magnesium sulfate hydrate Na2Mg(SO4)2・4H2O May be either a natural mineral or a laboratory product. |
35 | White crystalline powder | Aluminum, sulfur, potassium and oxygen | Alunite ICDD PDF 73-1652 | Alunite, K(Al3(OH)6(SO4)2 May be either a natural mineral or a laboratory product. |
36 | Crystalline fragments, colorless, traces of natural faces, conchoidal fracture | Silicon, oxygen, aluminum and fluorine | Topaz, aluminum fluosilicate. ICDD PDF 12-0765 | Topaz, Al2SiO4(F,OH)2 |
37 | Greyish fragments without particular features | Aluminum and oxygen with some impurities | Chrysoberyl ICDD PDF 78-0958 | Chrysoberyl, Al2BeO4 EDS did not determine the presence of beryllium, due to its low atomic mass |
38 | Hyaline yellowish fragments | Aluminum and oxygen | Corundum ICDD PDF 81-2267 | Corundum, Al2O3 |
39 | A white-grayish powder of metallic appearance | Aluminum and oxygen with impurities of copper and iron | Aluminum ICDD PDF 04-0787 | Aluminum, Al Impurities of Cu and Fe in the powder |
40 | White porcelanaceous fragments, conchoidal fracture. | Silicon, aluminum and oxygen | Beryl ICDD PDF 84-1141 | Beryl, Be3Al2Si6O18 EDS did not determine the presence of beryllium, due to its low atomic mass |
---|---|---|---|---|
41 | Dark, blackish fragments with conchoidal fractures | Oxygen, aluminum, calcium, iron and silicon, REE elements (La, Ce, Nd) | The spectrum is probably matching the Allanite’s one | Allanite (epidote group) (Ca,REE)2(Fe,Al)3(SiO4)3(OH) XRPD spectrum shows a low crystallinity, probably due to a radiation damage (metamictization) of the crystalline structure |
42 | Yellow and dark yellow fragments, no cleavage, conchoidal fracture | Oxygen, silicon and zirconium | Zircon ICDD PDF 83-1375 | Zircon, ZrSiO4 |
43 | Blackish, dark fragments with no distinctive features | Oxygen, carbon, fluorine and REE elements (La, Ce, Nd) | Parasite ICDD PDF 47-1832 and Bastnaesite ICDD PDF 11-0340 | Bastnaesite, CeCO3F Parisite, Ca(Ce,La)2F2(CO3)3 Probably a natural blend of the two minerals, used as standard for REE carbonates. |
44 | Greyish-green fragments | Phosphor, oxygen, thorium, calcium, REE elements (Ce, La, Nd) | Neodymium phosphate ICDD PDF 83-0654 | Monazite, (Ce,REE)PO4 |
45 | Black fragments | Manganese, sulphur | Alabandite ICDD PDF 88-2223 | Alabandite, (MnS) |
46 | Black fragments, with fibrous appearance. Black streak | Manganese and oxygen | Pyrolusite ICDD PDF 72-1984 | Pyrolusite, MnO2 |
47 | Pink fragments with cleavage traces, low hardness | Manganese, oxygen, carbon and a minor amount of calcium | Rhodochrosite ICDD PDF 44-1472 | Rhodochrosite, MnCO3 |
48 | Pink fragments without any cleavage | Silicon, oxygen, manganese and minor amount of calcium and magnesium | Rhodonite ICDD PDF 83-2212 and Bustamite ICDD PDF 85-1034 | Rhodonite (magnesian), (Mn,Mg)SiO3 Bustamite, (Ca,Mn)SiO3 Probably a natural mix of the two Mn-rich silicates Rhodonite and Bustamite |
49 | Sand | Oxygen, silicon, sodium, potassium and calcium | Quartz ICDD PDF 86-1629 and Albite ICDD PDF 09-0466 | Quartz, sodic feldspar, potassic feldspar Sand, mainly composed of Quartz and Feldspars. |
50 | Intense yellow fragments, vitreous, with some cleavage | Zinc, sulphur and iron | Pyrrothite ICDD PDF 76-2308 and Sphalerite ICDD PDF 77-2100 | Pyrrothite (Fe7S8) Sphalerite (ZnS) A mix of iron and zinc sulphides |
51 | Pale yellowish powder, with some metallic lustre | Iron, sulphur and oxygen | Pyrite ICDD PDF 89-3057 | Pyrite, FeS2 The sample was probably made of crushed Pyrite, strongly oxidized during a century. |
52 | Black fragments | Mainly iron and oxygen, some aluminum and calcium in small portions | Magnetite ICDD PDF 88-0315 | Magnetite, Fe3O4 Impurities of silicates |
53 | Dark reddish fragments with fibrous appearance | Iron and oxygen, minor amount of aluminum and silicon | Hematite ICDD PDF 89-0599 | Hematite, Fe2O3 |
54 | Reddish-yellowish dark fragments, fibrous appearance | Oxygen and iron | Goethite ICDD PDF 29-0713 | Goethite, FeO(OH) |
55 | Rhombohedrical shaped fragment, dark yellow | Iron, oxygen and carbon | Siderite ICDD PDF 83-1764 | Siderite, FeCO3 |
56 | Grey-greenish fragments with conchoidal fracture | Iron, phosphor, oxygen and minor amount of sodium, aluminium. | Natrodufrenite ICDD PDF 35-0570 | Vivianite, Fe3(PO4)2・8H2O The sample was probably vivianite, altered in Natrodufrenite |
57 | White, dusty fragments | Iron, arsenic and oxygen. | Scorodite ICDD PDF 37-0468 | Scorodite, FeAsO4・2H2O |
---|---|---|---|---|
58 | Greenish fragments | Iron, sulphur and oxygen, with sodium as minor element | Copiapite ICDD PDF 71-1546 and sodium iron sulfate ICDD PDF 29-1218 | Copiapite, Fe5(SO4)6(OH)2・20H2O sodium iron sulphate, Na6Fe(SO4)4 Original sample was Copiapite, slightly altered with formation of iron sulphates |
59 | Dark grey fragments of metallic lustre | Sulphur and antimony | Stibnite ICDD PDF 74-1046 | Stibnite, Sb2S3 |
60 | Light grey fragments with metallic lustre | Arsenic, nickel, cobalt and minor amount of sulphur and iron | Skutterudite ICDD PDF 25-0118 | Ni-Skutterudite, (Co, Ni, Fe)As3 |
61 | A very dark, black powder and fragments | Manganese and oxygen, small amount of calcium and magnesium | The spectrum shows a very low degree of crystallinity. | WAD (“Psilomelane”) A mix of manganese oxide |
62 | Apple green fragments with crusty appearance | Nickel and oxygen, with small amount of arsenic | The spectrum shows a very low degree of crystallinity. | Nepouite The sample is the Ni homologous of Chrysocolla, a mix of various Ni-silicate with different hydration degree and low crystallinity, deriving from Ni-sulphide alteration |
63 | Greyish-metallic fragments | Nickel and arsenic | Nickeline ICDD PDF 75-0603 | Nickeline, NiAs |
64 | Greyish-black fragment, crystalline | Nickel, antimony, sulphur, arsenic | Ulmannite ICDD PDF 83-1221 | As-Ulmannite, NiSbS |
65 | Missing sample | |||
66 | Angular gold-yellow vitreous fragments | Sulphur and zinc | Sphalerite ICDD PDF 65-0309 | Sphalerite, ZnS |
67 | Angular blackish fragments with submetallic lustre | Sulphur, zinc and minor iron | Ferroan Sphalerite ICDD PDF 89-4938 | Iron-rich sphalerite, (Zn,Fe)S The iron rich variety of sphalerite often known as “marmatite” |
68 | White sub-hyaline fragments with traces of cleavage | Zinc, oxygen and carbon | Smithsonite ICDD PDF 83-1765 | Smithsonite, ZnCO3 |
69 | Blackish crystalline fragments with good pseudo-cubic cleavage | Lead and sulphur | Galena ICDD PDF 65-0135 | Galena, PbS |
70 | Black fragments without cleavage | Sulphur, antimony and minor iron | Berthierite ICDD PDF 24-0509 Iron sulphide ICDD PDF 65-1211 Iron sulfate ICDD PDF 73-1057 | Berthierite, FeSb2S4 A mixing of Berthierite and minor Pyrite, oxidized during time |
71 | Hyaline whitish fragments with cleavage traces and natural flat surfaces | Lead, phosphor, oxygen and minor amount of calcium, | Pyromorphite ICDD PDF 73-1729 | Pyromorphite, Pb5(PO4)3Cl |
72 | White fragments | Lead, oxygen and carbon | Cerussite ICDD PDF 76-2056 | Cerussite, PbCO3 |
73 | Orange crystalline fragments | Lead, chromium and oxygen | Crocoite ICDD PDF 73-1332 | Crocoite, PbCrO4 |
75 | Brown-reddish crystalline fragments | Tin and oxygen | Cassiterite ICDD PDF 77-0447 | Cassiterite, SnO |
76 | Elongated steel-greyish fragments | Bismuth and sulphur | Bismutinite ICDD PDF 65-3884 | Bismutinite, Sb2S3 |
77 | Blackish fragments | Uranium, oxygen, and minor calcium, silicon and iron | Uraninite ICDD PDF 47-1879 | Uraninite, UO2 |
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78 | Black lustre fragments | Copper and sulphur | Chalcocite ICDD PDF 33-0490 | Chalcocite, Cu2S Quartz-impure chalcocite |
79 | Blackish fragments | Copper, antimony and sulphur | Tetrahedrite ICDD PDF 42-0561 | Tetrahedryte, Cu12Sb4S13 The sample also contains pyrite and iron/copper oxides |
80 | Greenish black fragments with alterations | Copper, sulphur, iron and oxygen | Chalcopyrite ICDD PDF 83-0983 | Chalcopyrite, CuFeS2 The sample shows alteration and oxidation of the surface |
81 | Dark, reddish fragments | Copper and oxygen | Cuprite ICDD PDF 78-2076 | Cuprite, Cu2O |
82 | Reddish fragments with deep green little crystals | Sulphur, oxygen and copper | Brochantite ICDD PDF 43-1458 | Brochantite, Cu4(SO4)2(OH)6 |
83 | Green earthy fragments with traces of cleavage | Copper, oxygen and carbon | Malachite ICDD PDF 41-1390 | Malachite, Cu2(CO3)(OH)2 |
84 | Earthy light blue fragments | Silicon, oxygen, copper and calcium as trace element | Malachite ICDD PDF 41-1390 | Malachite, Cu2(CO3)(OH)2 Chrysocolla |
85 | Red globular fragments | Mercury and sulphur | Cinnabar ICDD PDF 89-0438 | Cinnabar, HgS Small globular aggregates of Cinnabar in clay matrix |
86 | Blackish, earthy mass with no cleavage | Sulphur, antimony, copper and zinc, minor arsenic and iron | Tetrahedrite ICDD PDF 88-0282 | Tetrahedrite, Cu12Sb4S13 Tetrahedryte with a little amount of S and Zn as vicariant of Sb and Cu respectively |
87 | Whitish-green ductile fragments | Silver and chlorine | Chlorargirite ICDD PDF 01-1031 | Chlorargirite, AgCl |
88 | Small silvery filamentous fragments | Silver and small amount of oxygen. | Silver ICDD PDF 03-0921 | Silver, Ag |
89 | Ductile steel-grey fragments | Silver and sulphur, with a small amount of oxygen | Acanthite ICDD PDF 14-0072 | Acanthite, Ag2S The small amount of identified oxygen is probably due to surface oxidation |
90 | Blackish fragments with deep red tinge | Silver, sulphur and antimony | Pyrargiryte ICDD PDF 77-0329 | Pyrargyrite, Ag3SbS3 |
91 | Pitch black fragments with conchoidal fracture | Niobium, oxygen, iron, manganese and minor tantalum, uranium and titanium | Columbite ICDD PDF 84-1020 | Columbite, FeNb2O6 |
92 | Blackish-brownish fragments | Oxygen and titanium | Rutile ICDD PDF 87-0710 | Rutile, TiO2 |
93 | Black pitchy fragments | Iron, titanium and oxygen | Ilmenite ICDD PDF 75-1210 | Ilmenite, FeTiO3 |
94 | Steel grey fragments with traces of cleavage | Sulphur and antimony | Stibnite ICDD PDF 74-1046 | Stibnite, Sb2S3 |
95 | Steel grey fragments with good cleavage | Calcium, oxygen, tungsten and iron | Hubnerite ICDD PDF 12-0727 | Hubnerite, (Fe,Mn)WO4 Scheelite, CaWO4 Mn-poor Hubnerite and traces of Scheelite |
96 | Pale yellow fragments with good cleavage | Calcium, oxygen, tungsten | Scheelite ICDD PDF 41-1431 | Scheelite, CaWO4 |
97 | Silvery plates, flexible | Molybdenum and sulphur | Molybdenite ICDD PDF 65-3656 | Molybdenite, MoS2 |
98 | Yellow orange small crystals | Lead, molybdenum and oxygen | Wulfenite ICDD PDF 74-1075 | Wulfenite, PbMoO4 |
99 | Greenish black fragments, no trace of cleavage | Chromium, oxygen, magnesium, aluminium and iron | Ferroan-magnesiochromite spinel ICDD PDF 09-0353 | Spinel (magnesiochromite, ferroan) (Mg,Fe)(Cr,Al)2O4 | ||
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100 | Grey dusty fragments | Arsenic, with small amount of oxygen and antimony | Arsenic ICDD PDF 72-1048 | Arsenic, As Probably altered on surface with formation of trivalent arsenic oxide (Arsenolite) | ||
101 | Orange reddish crystals, with vivid lustre | Sulphur and arsenic | Realgar ICDD PDF 71-2434 | Realgar, AsS | ||
102 | Yellow brownish light fragments, rounded aspect | Carbon | Amorphous | Amber The identification was obtained also by mean of combustion test | ||
103 | Yellowish-brownish granules, very soft | Carbon, oxygen | Amorphous | Beeswax Final identification has been obtained with combustion and fusion test. The mass was contaminated by different substances (Feldspar, Galena and others) | ||
104 | White small scales | Oxygen | Boric acid ICDD PDF 30-0199 | Boric acid (sassolite), H3BO3 May be either a natural mineral or a laboratory product. | ||
105 | Vitreous greenish black fragment with conchoidal fracture | Silicon, aluminium, oxygen, magnesium, sodium, iron with some titanium | Dravite (tourmaline group) ICDD PDF 85-1816 | Dravite (tourmaline group) NaMg3Al6(BO3)3Si6O18(OH)4 | ||
106 | Vitreous greenish grey fragments | Silicon, aluminium, calcium, magnesium, iron and manganese | Axinite ICDD PDF 29-0344 | Mg-axinite Ca2(Fe2+, Mg, Mn2+)Al2BO3Si4O12(OH) | ||
107 | White powder | Magnesium, chlorine and oxygen | Magnesium chloroborate ICDD PDF 85-0899 | Magnesium chloroborate ClMg3B7O13 Probably a laboratory product | ||
108 | Transparent, colourless vitreous fragments | Silicon, oxygen | Quartz ICDD PDF 86-1629 | Quartz, SiO2 | ||
On the other hand, it has not been possible to determine the manufacturing date and origin even if the probe- tubes’ type, the box design and its wood kind suggest a German builder and a period around the second half of XIX century.
The general features of the wooden box show that it is designed either for being carried out during mineralogical missions or for didactic purposes. These didactic-scientific collections have played in their time a fundamental role for largely improving the chemical, geological and mineralogical level of knowledge just before and during the important period of the so-called industrial revolution. Many data are going to be collected about similar collections (private and public) in order to characterize the importance of some mineralogical species, which can be considered as reference terms for the industrial development.
The whole set shows a good correspondence with the description of mineralogical and didactical collections and kits described in several old advertising brochures and catalogues, issued by companies who, since the mid ‘800, started designing and selling scientific and technological tools and equipment: the German Krantz, based in Bonn and Hugershoff, based in Leipzig or Gregory & Bottley, based in London. In particular, most these companies built up and supplied their educational collections, like the wooden box, examined in this study, consisting of a minimum of 50 to a maximum of about 170/200 different mineralogical and/or chemical samples each. Just to get an economical evaluation of the wooden box of the present study, a similar one containing 105 samples arranged according Kobell system was costing around 30.00 D.M. after having been quoted by the Franz Hugershoff’s catalogue of 1911.
A countertype of the same box (104 fragments of minerals in neat case for blowpipe analysis) was offered in 1936 by the firm Gregory & Bottley at a price of around 1.5 £. Today, the approximate and estimated current prize of both boxes would be between 450 and 750?
EmanueleCosta,AlessandroDelmastro,Luca DiGregorio,SilviaRonchetti,Massimo UmbertoTomalino, (2016) XRPD and SEM-EDS Identification of a Mineralogical Standards Kit Forming a 19th Century Collection for Educational Analysis. Journal of Minerals and Materials Characterization and Engineering,04,73-86. doi: 10.4236/jmmce.2016.41008