130-A23-2
Displaying 1 - 49 of 49
Catalog # | Name | Description | ||
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1 | 00.2.11.283.0006 | Melanterite | Melanterite is one of only a few water soluble sulfate minerals. It forms in the near-surface secondary oxidation zone of ore deposits usually late in their development. In many mines, melanterite is an ongoing precipitate or efflorescent forming white to green encrustations, crystal aggregates and stalactites right on the sides of the mine's shafts. The primary source of the iron for melanterite is iron sulfides such as pyrite, pyrrhotite, marcasite and chalcopyrite. A technique for removing copper from the copper sulfate mineral chalcanthite is responsible for the naming of an alternate name for melanterite. Chalcanthite, like melanterite, is soluble in water and it thus makes a solution of copper sulfate. If metallic iron is added to the solution, then metallic copper precipitates, leaving a solution of iron sulfate. This left-over solution has the same composition as a solution made from dissolving melanterite. The alternate name for melanterite is "copperas", from the Greek meaning "copper water", an allusion to the left-over solution. In a way, this could be thought of as "copper-providing water". Attractive crystals of melanterite with a beautiful blue-green color are know to exist and are sought after. The shades toward blue come from impurities of copper which can substitute for as much as one third of the iron. The more copper, the bluer the crystals. Generally melanterite is known as having a white or green color. Melanterite is also the name of a group of only five monoclinic sulfates of which melanterite is the only somewhat common member. Members of this group have the same basic structure as melanterite, but can have in place of iron, ions of manganese, zinc, cobalt and copper. These are the members of the Melanterite Group: Bieberite (Hydrated Cobalt Sulfate), Boothite (Hydrated Copper Sulfate), Mallardite (Hydrated Manganese Sulfate), Melanterite (Hydrated Iron Sulfate), Zinc-melanterite (Hydrated Zinc Copper Iron Sulfate) PHYSICAL CHARACTERISTICS: Color is white, green, yellowish green or blue-green. Luster is vitreous to silky. Transparency: Crystals are translucent to slightly transparent. Crystal Habits include stubby prismatic or blocky to tabular crystals, sometimes as pseudo-octahedrons. Also acicular, fibrous and capillary and found as encrusting, stalactitic and concretionary masses. Cleavage is perfect in one direct but only distinct in another. Fracture is conchoidal. Hardness is 2 Specific Gravity is approximately 1.9 (well below average). Streak is white. Other Characteristics: Is soluble in water and may deteriorate with absorption of water. The taste has a sweet, astringent and metallic character. Associated Minerals are epsomite, chalcanthite, gypsum, pyrite, pyrrhotite, marcasite and chalcopyrite. Notable Occurrences include Minas de Rio Tinto, Spain; Rammelsberg, Harz Mountains, Germany and Falun, Sweden; and in the United States at Ducktown, Tennessee; South Dakota; Colorado; Bigham Canyon, Utah; Comstock Lode, Lincoln County, Nevada; Butte, Montana; at several mines in Arizona and at The Geysers in Sonoma County and at Leona Heights, Alameda County, California. Best Field Indicators are crystal habit, low density, associations, solubility in water, taste and color. | |
2 | 00.2.5.137.0002 | Tungstite | On Ferberite. With Ward's label. Color: GR, WH | |
3 | 1970.74.1004M | Hanksite | Gray, botriodal. | |
4 | 1970.74.1091M | Gypsum var. Selenite | Selenite crystal. | |
5 | 1970.74.1092M | Gypsum var. Selenite | Clear crystal. | |
6 | 1970.74.1214M | Linarite | Blue coating on quartz. | |
7 | 1970.74.1254M | Gypsum var. Selenite | Var. selenite; clear tannish cleavage fragments. | |
8 | 1970.74.1333M | Gypsum var. Selenite | Gray translucent crystals. | |
9 | 1970.74.1334M | Gypsum var. Selenite | Clear, gray crystals - selenite. | |
10 | 1970.74.1413M | Gypsum var. Selenite | Bum nodule. | |
11 | 1970.74.1653M | Gypsum var. Selenite | None | |
12 | 1987.3.0024 | Gypsum | Transparent, tan plate. | |
13 | 1990.53.0072 | Gypsum | Var. selenite, single crystals & large cluster w/sand inclusions; clear & brown | |
14 | 1990.53.0073 | Gypsum | Var. selenite, gray crystal group. | |
15 | 1990.53.0074 | Gypsum | Massive, iron stained white with cleavage faces | |
16 | 1990.53.0075 | Gypsum | Var. selenite, clear gray crystals w/swallowtail formation | |
17 | 1990.53.0076 | Gypsum | Curved cream crystals. | |
18 | 1990.53.0077 | Gypsum | Var. selenite; crystals heavily sand-included brown & clear | |
19 | 1990.53.0078 | Gypsum | Selenite crystal cluster; clear. | |
20 | 1990.53.0079 | Gypsum | Var. selenite, flat, tan sand included crystals; a. and b. | |
21 | 1990.53.0080 | Gypsum | Var. selenite, "hourglass" crystals; singles & clusters. | |
22 | 1990.53.0080a | Gypsum | Var. selenite, cluster of fine sand-included crystals | |
23 | 1990.53.0082 | Gypsum | None | |
24 | 1990.53.0083 | Gypsum | Flat cluster of thick gray transparent crystals. | |
25 | 1990.53.0216 | Gypsum | Var. selenite, tan attached "roses". | |
26 | 1990.53.0217 | Gypsum | Var. selenite, tan "rose". | |
27 | 1990.53.0218 | Gypsum | Var. selenite, single & crystal groups. | |
28 | 1990.53.0219 | Gypsum | Var. selenite, reddish brown "rose". | |
29 | 1990.53.0220 | Gypsum | Flat, orange selenite with inclusions. | |
30 | 1990.53.0221 | Gypsum | Var. selenite, 14 1/2" connected "roses"; Note: Specimens not numbered - not suitable space. | |
31 | 1990.53.0222 | Gypsum | Reddish brown selenite "rose". | |
32 | 1990.53.0223 | Gypsum | Var. selenite. clusters of connected "roses"; Note: specimens not numbered - no suitable surface. | |
33 | 1990.53.0224 | Gypsum | Var. selenite. cluster of white crystals. | |
34 | 1990.53.0225 | Gypsum | Var. selenite; clear, clean ball of crystals. | |
35 | 1990.53.0226 | Gypsum | Var. selenite; cluster of sand encrusted & included crystals | |
36 | 1990.53.0227 | Gypsum | Miniature - cluster of sandy brown crystals; TN - singles. | |
37 | 1990.53.0228 | Gypsum | Clear, clean crystal ball. | |
38 | 1990.53.0229 | Gypsum | None | |
39 | 1990.53.0232 | Gypsum | Var. selenite roseick gray transparent crystals. | |
40 | 1990.53.0236 | Gypsum | None | |
41 | 1990.53.0242 | Gypsum | Var. selenite; specimen d - single clear crystal; specimens abcd - dlusters of small crystals with 2 or 3 larger protruding crystals | |
42 | 1990.53.0282 | Gypsum | Var. satin spar; white, striated. | |
43 | 1990.53.0365 | Gypsum | Transparent, golden, massive with smaller clear crystals attached | |
44 | 1990.53.0366 | Gypsum | Clear crystals - large, blocky. | |
45 | 1994.11.0006 | Gypsum | Variation, selenite; typical. Color: CL | |
46 | 1994.11.0007 | Gypsum | Var. selnite; typical large crystal. Color: CL,GY | |
47 | 1995.36.0027 | Gypsum | Var. selenite, with curved crystals. Color: WH | |
48 | 1996.16.0018 | Gypsum | Variety selenite. Color: WH,BR | |
49 | 2006.15.0007 | Gypsum (Selenite rose variety) | 340 gram uniformly gray colored specimen of gypsum. This particular type is known as selenite rose because of the petal like structure of the large crystals it contains. Color: GY |