Adamite: Ojuela Mine, Mapimi, Mexico (0.86). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Exceedingly rare as a cut gem, although the mineral occurs in many localities. Much too soft and fragile for jewelry; strictly a collector item.
Adamite Value
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Adamite Information
| Data | Value |
| Name | Adamite |
| Crystallography | Orthorhombic; crystals elongated or equant; druses, radial aggregates, and spheroids on matrix. |
| Colors | Colorless, pale green, yellowish green, yellow (various shades), bluish green, green (contains Cu); rose and violet shades (color zoned, contains Co). |
| Luster | Vitreous |
| Hardness | 3.5 |
| Density | 4.32-4.68 (red-violet) |
| Cleavage | Good 1 direction. Fracture subconchoidal to uneven. |
| Dispersion | Strong |
| Stone Sizes | Violet crystals noted up to 1 cm long and transparent, would yield stones up to about 1-2 carats. Green material usually not clean, would provide only small faceted gems (1-3 carats). PC: 4.38 (pink, Mexico) |
| Luminescence | Intense green in SW, LW; also lemon yellow in SW. |
| Spectral | Not diagnostic. |
| Formula | Zn2(AsO4)OH + Co, Cu. |
| Pleochroism | Colorless/ blue-green/yellow-green. Pale rose/ pale rose/ pale purple. Pink/ pale rose/colorless. |
| Locality |
α |
β |
γ |
Birefringence |
| Mapimi, Mexico (reddish) |
1.712 |
1.736 |
1.760 |
0.048 |
| Mapimi, Mexico (rose) |
1.710 |
1.735 |
1.759 |
0.049 |
| Mapimi, Mexico (violet) |
1.710 |
1.735 |
1.758 |
0.048 |
| Mapimi, Mexico (green) |
1.722 |
1.742 |
1.763 |
0.041 |
| Tsumeb, Namibia (Cu) |
1.742 |
1.768 |
1.773 |
0.031 |
| Tsumeb, Namibia (Co) |
1.722 |
1.738 |
1.761 |
0.039 |
| Laurium, Greece |
1.708 |
1.734 |
1.758 |
0.050 |
Biaxial (+); 2V = 15° (Cu. Var.) to 88°
Large variations in composition lead to wide variations in optical properties.
Occurrence: Secondary mineral in the oxidized zone of ore deposits.
Utah (various localities); California; Nevada.
Laurium, Greece: often containing copper, in lovely blue and green shades.
Mapimi, Mexico: fine sprays of crystals in limonite matrix, from the Ojuela Mine.
Tsumeb, Namibia: fine crystals, sometimes colored purple by cobalt.
Cap Garonne, France.
Also Chile, Italy, Germany, Turkey, Algeria.
Comments: Exceedingly rare as a cut gem, although the mineral occurs in many localities. Much too soft and fragile for jewelry; strictly a collector item.
Name: After Mr. Gilbert Adam, mineralogist, of Paris, who supplied the first specimens for study.
