Foitite
A variety of Tourmaline Group

What is Foitite?
Optical Properties
- Pleochroism
- Strong: pale lavender, dark blue
- Optical Character
- Uniaxial negative
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Foitite 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.
Foitite Localities Map
See where Foitite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Quick Facts
Physical Properties
- Color
- Dark indigo with purple tints to bluish-black
- Hardness (Mohs)
- 7
- Density
- 3.14 g/cm³
- Streak
- Greyish-white
Chemical Properties
- Chemical Formula
- (□,Na)(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3OH
- Elements
- Al, B, Fe, H, O, Si

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Foitite FAQs
How do I identify Foitite?
Foitite can be identified by its hardness of 7 on the Mohs scale, Dark indigo with purple tints to bluish-black color. Look for these key characteristics when examining specimens.
What color is Foitite?
Foitite typically appears in Dark indigo with purple tints to bluish-black. Color can vary depending on impurities and formation conditions.
How hard is Foitite?
Foitite has a hardness of 7 on the Mohs scale. This makes it a relatively hard mineral suitable for jewelry.

