Variscite
Variscite is a phosphate mineral that takes on a green to blue-green color due to the influence of Cr (chromium) or Fe (iron). It is found as masses consisting of fine crystalline grains, and its structure is considered to be denser than that of Turquoise. Specimens from Tooele County, Utah, USA, are particularly high quality and are sometimes referred to by the trade name "Utahlite."
Variscite, appealing for its green to blue-green color and dense texture
Basic Information
| English Name | Variscite |
|---|---|
| Japanese Name | Variscite |
| Chemical Composition | Al[PO4]・2H2O |
| Crystal System | Orthorhombic |
| Hardness | 3.5–4.5 |
| Specific Gravity | Approx. 2.4 |
| Transparency | Translucent to Opaque |
Characteristics & Variations
- Color Characteristics: Can turn green to blue-green due to Cr and Fe.
- Structure: Found as masses of fine crystalline grains; characterized by a dense texture (considered denser than Turquoise).
- Quality Source: Specimens from Tooele County, Utah, USA, are of particularly high quality and are known by the alternate name "Utahlite."
Varieties
- Agatized Variscite (Silicified Variscite): Specimens hardened by the silica content of Agate or Chalcedony.
Source, Alternate Names, Treatments & Similar Stones
Trade Names:
Because green-toned Variscite resembles Turquoise, it is often sold under misnomers for Turquoise, such as:
- Utah Turquoise
- Australian Turquoise
Treatments:
- Dyeing & Impregnation: Dyeing and impregnation with synthetic resins for stabilization purposes are sometimes performed.
- Heat Treatment: For stones with high iron content, heating may oxidize the iron, causing the stone to change to a brownish-pink color.
Similar Stones:
- Turquoise, resembles Turquoise with high Fe content and strong green tones.
Caution: Trade names such as "Utah Turquoise" can easily lead to confusion with Turquoise. Furthermore, as treatments such as impregnation and dyeing may be applied, it is safest to clearly state both the "true identity of the material" and "whether it has been treated" during procurement and sales.