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Sulfates

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Catalog # Name Description
1 00.2.10.150.0005 Gypsum

Small seam of clear crystals.

2 00.2.10.157.0003 Barite

Calcite vein-stuff in carboniferous shale.

3 00.2.10.177.0015 Gypsum

Translucent, blocky crystal group.

4 00.2.10.189.0003 Barite

Pinkish blades on dark calcite matrix with clear calcites.

5 00.2.11.283.0001 Heubnerite

Crystals in quartz.

6 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.

7 00.2.13.501.0014 Wolframite None
8 00.2.15.303.0003 Barite

Barite/sandstone rose.

9 00.2.15.304.0009 Gypsum

Concretion.

10 00.2.15.330.0011 Barite

Misidentified as dolomitic material.

11 00.2.15.330.0012 Barite

Misidentified as dolomitic material.

12 00.2.15.331.0002 Wulfenite None
13 00.2.15.331.0003 Scheelite

Pale gray, massive.

14 00.2.15.331.0007 Wulfenite

Small, golden cubes in vugs.

15 00.2.23.705.0029 Barite

Massive, pink.

16 00.2.23.707.0012a Gypsum

Curved crystal groups on matrix, selenite.

17 00.2.3.657.0007 Scheelite

Massive, grey.

18 00.2.3.657.0008 Wolframite (Ferberite)

Black, some crystal faces showing.

19 00.2.3.659.0005 Wolframite (Ferberite)

With Tunctate decomposition.

20 00.2.3.659.0006 Wolframite (Ferberite)

Small, sparkly crystals on matrix.

21 00.2.3.659.0007 Wolframite (Ferberite)

Blades of Ferberite in quartz.

22 00.2.3.659.0008 Wolframite

Massive pyrite with copper crystals.

23 00.2.3.688.0002 Gypsum

Variety alabaster, cut & polished semi-circle.

24 00.2.5.137.0002 Tungstite

On Ferberite. With Ward's label. Color: GR, WH

25 00.2.6.195.0004 Celestite

Blue, fibrous.

26 00.2.6.195.0005 Celestite

Clear blue-gray chunks.

27 00.2.6.195.0009 Celestite

Pale gray. Possibly not celestite.

28 00.2.6.196.0001 Barite

One specimen - tan calcite crystals.

29 00.2.6.196.0002 Barite

Massive, white.

30 00.2.6.196.0003 Barite

White, lamellar.

31 00.2.6.196.0004 Barite

Crystalline massive.

32 00.2.6.196.0005 Barite

White interlocked crystals.

33 00.2.6.196.0006 Barite

White, lamellar, massive.

34 00.2.6.196.0007 Barite

Massive, white (heavy spar).

35 00.2.6.196.0011 Barite

White barite crystals with malachite.

36 00.2.6.196.0013 Barite

Clear, gray tabular crystals.e matrix with clear calcites.

37 00.2.6.197.0001 Gypsum

Impure; with curved crystals of selinite. In exhibit from 1992-2006

38 00.2.6.197.0002 Gypsum

Dark gray, mssive, showing cleavage faces.

39 00.2.6.197.0005 Gypsum

White, massive, showing cleavage planes.

40 00.2.6.197.0007 Gypsum

White, massive; initials E. R. scratched on surface

41 00.2.6.197.0008 Gypsum

Var. alabaster; white, massive.

42 00.2.6.197.0009 Gypsum

Gypsum w/clay; gray, some clear crystals to 3/4"

43 00.2.6.198.0002 Gypsum

Satin spar.

44 00.2.6.198.0003 Gypsum

Fibrous, white to orangish.

45 00.2.6.198.0007 Gypsum

Small brown crystals encrusted with rock salt.

46 00.2.6.198.0009 Gypsum

Ver. selenite; 2 crystals.

47 00.2.6.198.0011 Gypsum

Gypsum crystal in clay.

48 00.2.6.198.0012 Gypsum

Gray crystals.

49 00.2.6.198.0013 Gypsum None
50 00.2.6.198.0014 Gypsum

White, massive, pieces of a 3/4" slab, unpolished var. alabaster

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