Sulfates

Displaying 1 - 50 of 288
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