Faustite
A variety of Turquoise Group
What is Faustite?
The IMA approved mineral faustite, named after the American mineralogist and petrologist with the U.S. Geological Survey (USGS) Dr. George Tobias Faust, is a member of the triclinic turquoise group of hydrous phosphates with the following chemical composition: ZnAl6(PO4)4(OH)8·4H2O Some divalent copper generally replaces the zinc position. Faustite is the zinc rich analogue of turquoise having almost four times as much zinc than copper in its crystal structure. Trivalent (ferric) iron may replace some of the aluminum. Minor amounts of calcium may also be present. It has a hardness of 4.5 - 5.5 on the Mohs scale of mineral hardness and aside from having a slightly lower hardness, it may be difficult to distinguish it from turquoise in hand specimens. Faustite has a blue-green to apple green color in polished cabochons, and may be presented as a turquoise imitation, and it may also be treated with stabilizers for jewelry making.
Optical Properties
- Refractive Index
- 1.612
- Optical Character
- Biaxial positive
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Faustite before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Faustite Localities Map
See where Faustite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
The Meaning
As a member of the turquoise umbrella, faustite has been associated as a holy stone for thousands of years. The color of these stones is thought to be associated with the ancient Persian star Tishtrya, which is known as the "water guard" star. They wore stones containing faustite to protect against unnatural death. This has made it a popular religious stone for ages.
Quick Facts
Physical Properties
- Color
- Apple-green
- Hardness (Mohs)
- 5.5
- Density
- 2.99 g/cm³
- Streak
- White to pale yellow-green
Chemical Properties
- Chemical Formula
- ZnAl6(PO4)4(OH)8 · 4H2O
- Elements
- Al, H, O, P, Zn
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Faustite FAQs
How do I identify Faustite?
Faustite can be identified by its hardness of 5.5 on the Mohs scale, Apple-green color. Look for these key characteristics when examining specimens.
What color is Faustite?
Faustite typically appears in Apple-green. Color can vary depending on impurities and formation conditions.
How hard is Faustite?
Faustite has a hardness of 5.5 on the Mohs scale. This gives it moderate hardness.