Bastnäsite

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Physical & Optical Properties

Mohs Hardness 4,0 – 4,5
Specific Gravity 4,78 – 5,2
Refractive Index 1,72 – 1,82
Crystal System Hexagonal
Luster Vitreous,Pearly
Cleavage Distinct,Poor
Fracture Uneven
Color various
Birefringence 0,1
Pleochroism Weak

Mohs Hardness

Mohs Hardness: 4,0 – 4,5
1 Soft10 Hard

Crystal System

a a c Hexagonal a = b ≠ c, α = β = 90°, γ = 120°

Value & Market

Price Tier Budget (< $50/ct)

About Bastnäsite

Bastnäsite is a rare earth fluorocarbonate mineral and one of the world's most important ore minerals for extracting lanthanide rare earth elements including cerium and lanthanum. It forms honey-yellow to waxy brown hexagonal crystals, rarely transparent enough for faceting, in carbonatites and alkaline igneous rocks. Major deposits occur at Mountain Pass in California and Bayan Obo in China; faceted gems are extreme rarities valued only by advanced collectors.

Jewelry Use

Durability 3/10

Science FYI Family

Frequently Asked Questions

What is Bastnäsite?
Bastnäsite is a rare earth fluorocarbonate mineral and one of the world's most important ore minerals for extracting lanthanide rare earth elements including cerium and lanthanum. It forms honey-yellow to waxy brown hexagonal crystals, rarely transparent enough for faceting, in carbonatites and alka
What is the hardness of Bastnäsite?
Bastnäsite has a Mohs hardness of 4.0 to 4.5, making it relatively soft for use in jewelry.
What color is Bastnäsite?
Bastnäsite is primarily Various.
How much does Bastnäsite cost?
Bastnäsite falls into the Budget (< $50/ct) price range. Prices vary based on color, clarity, cut, and origin.
What is the crystal system of Bastnäsite?
Bastnäsite belongs to the Hexagonal crystal system.

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