Sellaite

Q: What is Sellaite?

Sellaite is a rare magnesium fluoride mineral that forms colorless to white tetragonal prisms with a vitreous to pearly luster in hydrothermal veins and volcanic fumaroles. It was first described from the Sella Valley in Piedmont, Italy, and is also found in Vesuvian lavas and in evaporite deposits.

Q: What is the hardness of Sellaite?

Sellaite has a Mohs hardness of 5.0 to 5.5, making it moderate for use in jewelry.

Q: How much does Sellaite cost?

Sellaite falls into the Budget (< $50/ct) price range. Prices vary based on color, clarity, cut, and origin.

Q: What is the crystal system of Sellaite?

Sellaite belongs to the Tetragonal crystal system.

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Physical & Optical Properties

Category Semi-Precious Gems

Mohs Hardness 5.0 – 5.5

Specific Gravity 3.14 – 3.16

Refractive Index 1.378 – 1.39

Crystal System Tetragonal

Luster Vitreous

Cleavage Distinct

Fracture Conchoidal

Color various

Birefringence 0.01

Mohs Hardness

Mohs Hardness: 5.0 – 5.5

1 Soft10 Hard

Crystal System

Value & Market

Price Tier Budget (< $50/ct)

Where to Buy Sellaite

Blue Nile Fine jewelry retailer

James Allen Gemstone jewelry

Brilliant Earth Ethically sourced gems

Amazon Wide selection

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About Sellaite

Sellaite is a rare magnesium fluoride mineral that forms colorless to white tetragonal prisms with a vitreous to pearly luster in hydrothermal veins and volcanic fumaroles. It was first described from the Sella Valley in Piedmont, Italy, and is also found in Vesuvian lavas and in evaporite deposits. Specimens are of primarily scientific interest, though transparent crystals have occasionally been faceted for mineral collectors.