Adamite Value, Price, and Jewelry Information
Although adamite occurs in many localities, it's very rarely cut as a gem. This mineral is much too soft and fragile for jewelry. However, collectors prize its intense fluorescence.
Adamite Value
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
Adamite Information
| Data | Value |
| Name | Adamite |
| Crystallography | Orthorhombic; crystals elongated or equant; druses, radial aggregates, and spheroids on matrix. |
| Refractive Index | 1.708-1.773 |
| Colors | Colorless; yellowish green, yellow in various shades (contains Fe); pale green, bluish green, green (contains Cu); rose and violet shades (color zoned, contains Co); purple (contains Mn). |
| Luster | Vitreous |
| Fracture | Subconchoidal to uneven |
| Hardness | 3.5 |
| Specific Gravity | 4.32-4.68 (red-violet) |
| Birefringence | See "Identifying Characteristics" below. |
| Cleavage | Good 1 direction |
| Dispersion | Strong |
| Luminescence | Intense green in SW, LW; also lemon yellow in SW. |
| Transparency | Translucent to transparent. |
| Absorption Spectrum | Not diagnostic. |
| Formula | Zn2(AsO4)OH + Co, Cu. |
| Pleochroism | Colorless/ blue-green/yellow-green. Pale rose/ pale rose/ pale purple. Pink/ pale rose/colorless. |
| Optics | Biaxial (+/-); 2V = 15° (Cu. Var.) to 88°. See “Identifying Characteristics” below. |
| Etymology | After Gilbert-Joseph Adam, the Parisian mineralogist who supplied the first specimens for study. |
| Occurrence | Secondary mineral in the oxidized zone of ore deposits. |
Comments
Adamite forms a series, as the zinc (Zn) analogue, with olivenite, the copper (Cu) analogue. This series has a distinct, intermediate member known as zincolivenite. (Don’t confuse olivenite with olivine).
The presence of numerous impurities can create various colors in adamites. For example, iron (Fe) can cause yellow hues. Cuprian (Cu bearing) varieties show green hues. Cobalt (Co) bearing specimens can show rose or purple/violet hues. Manganoan or manganese (Mn) bearing specimens may have purple/violet colors as well as pink and lavender.
Adamites can have an intense green fluorescence under either shortwave (SW) or longwave (LW) ultraviolet light. They may also show lemon yellow fluorescence under SW.
This specimen shows dozens of “pinwheel” adamite crystals on gossan matrix and intense neon green fluorescence. “Adamite,” Ojuela Mine, Mapimi, Durango, Mexico, 10.5 x 9.3 x 6.2 cm. © Rob Lavinsky, www.iRocks.com. Used with permission.
Identifying Characteristics
Due to wide variations in composition, optical properties can vary significantly.
| 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 |
Synthetics
Scientists have used synthetic specimens of the adamite-olivenite series for spectroscopy research. However, there is no known jewelry use for this material.
Enhancements
None known.
Sources
The Ojuela Mine in Mapimi, Mexico produces fine sprays of crystals in limonite matrix.
Tsumeb, Namibia also produces fine crystals, sometimes colored purple by cobalt.
Laurium, Greece yields specimens often containing copper, in lovely blue and green shades.
Other notable sources include:
- United States: California; Nevada; Utah (various localities).
- France: Cap Garonne.
- Algeria; Chile; Germany; Italy; Turkey.
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).
- Private Collection: 4.38 (pink, Mexico).
Care
Adamites have a low hardness of 3.5 and good cleavage. Thus, they make less than optimal pieces for jewelry use. You’ll find these stones more likely in gem collections as crystal specimens than in jewelry collections. See our gemstone jewelry cleaning guide for care recommendations.
