SMITHSONITE: Tsumeb, Namibia (cabochon ~ 50,faceted gems ~ 18, 12)
The blue-green smithsonite from New Mexico has been popular with collectors for many years. Pinkish colors are due to cobalt, yellow to cadmium. The low hardness of smithsonite makes it unsuited for jewelry, but properly cut faceted gems are magnificent. The dispersion is almost as high as diamond, and faceted stones have both rich color and lots of fire. Among the most beautiful are the yellowish stones from Tsumeb, Namibia.
Smithsonite Value
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Smithsonite Information
| Data | Value |
| Name | Smithsonite |
| Crystallography | Hexagonal (R). Crystals rhombohedral; massive, botryoidal, compact, stalactic. |
| Colors | White, gray, pale to deep yellow, yellowish brown to brown, pale green, apple green, blue-green, blue, pale to deep pink, purplish, rarely colorless. |
| Luster | Vitreous to pearly, earthy. dull. |
| Hardness | 4-45. |
| Density | 4.3—4.45. |
| Birefringence | 0.227. |
| Cleavage | Perfect rhombohedral. Brittle. |
| Dispersion | 0.037. |
| Stone Sizes | Beautiful cabochons up to many inches may be cut from the massive material from New Mexico, Sardinia, and other localities. Crusts in some localities are several inches thick. The pink material from Mexico is especially lovely. Facetable crystals are rare, known only from the African localities. and stones over 10 carats could be considered exceptional. Private Collection: 45.1 (dark yellow, emerald-cut. Tsumeb). |
| Luminescence | In SW, medium whitish blue (Japan), blue-white (Spain), rose red (England), and brown (Georgia, Sardinia). In LW, greenish yellow (Spain) and lavender (California). |
| Spectral | Not diagnostic. |
| Formula | ZnCO3 + Fe, Ca, Co, Cu, Mn, Cd, Mg, Pb. |
Optics: o= 1.848: e =1.621.
Uniaxial (-).
Other Tests: Effervesces in warm acids.
Occurrence: Smithsonite is a secondary mineral in the oxidized zone of ore deposits.
SMITHSONITE: Tsumeb, Namibia (8.00, 10.40)
Colorado; Montana; Utah.
Germany; Austria; Belgium; France; Spain; Algeria; Tunisia.
Kelly, Socorro County, New Mexico: blue and blue-green, massive crusts, fine color.
Marion County, Arkansas: yellow, banded crusts.
Laurium, Greece: fine blue and green crystals.
Sardinia, Italy: banded yellow material.
Tsumeb, Namibia: yellowish and pinkish crystals, also, green-facetable.
Broken Hill, Zambia: transparent crystals to 1 cm.
Australia: yellow.
Mexico: pink and bluish crusts; much variation in color.
SMITHSONITE: Kelly Mine, New Mexico (blue 5 inches), Mexico (other colors)
Comments: The blue-green smithsonite from New Mexico has been popular with collectors for many years. Pinkish colors are due to cobalt, yellow to cadmium. The low hardness of smithsonite makes it unsuited for jewelry, but properly cut faceted gems are magnificent. The dispersion is almost as high as diamond, and faceted stones have both rich color and lots of fire. Among the most beautiful are the yellowish stones from Tsumeb, Namibia.
Name: After James Smithson, the benefactor whose bequest founded the Smithsonian Institution in Washington. D.C.
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