Feodosiyite

A variety of Minerals

What is Feodosiyite?

Feodosiyite is a very rare chloride mineral, just recently approved, with the formula Cu11Mg2Cl18(OH)8•16H2O. Its structure is unique. Feodosiyite comes from the Tolbachik volcano, famous for many rare fumarolic minerals. Chemically similar minerals, chlorides containing both copper and magnesium, include haydeeite, paratacamite-(Mg) and tondiite.

Market Value Factors

Pricing varies for every rock and mineral, so use these universal factors to gauge Feodosiyite 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.

Applies to all rocks & minerals.

Quick Facts

Physical Properties

Color: Bright green
Hardness (Mohs): 3
Rock tumbling: Not recommended
Density: 2.563 g/cm³

Chemical Properties

Chemical Formula: Cu₁₁Mg₂Cl₁₈(OH)₈·16H₂O
Elements: Cl, Cu, H, Mg, O

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Feodosiyite FAQs

How do I identify Feodosiyite?

Feodosiyite can be identified by its hardness of 3 on the Mohs scale, Bright green color. Look for these key characteristics when examining specimens.

What color is Feodosiyite?

Feodosiyite typically appears in Bright green. Color can vary depending on impurities and formation conditions.

How hard is Feodosiyite?

Feodosiyite has a hardness of 3 on the Mohs scale. This makes it a soft mineral that can be scratched easily.