mineral

Blue Topaz

Aluminum Silicate Fluoride Hydroxide Al2SiO4(F,OH)2

Hardness: 8.0 on Mohs scale; Color: Swiss Blue; Luster: Vitreous; Crystal Structure: Orthorhombic; Specific Gravity: 3.49–3.57. Shows perfect basal cleavage.

Hardness: 8
Color: Swiss Blue
Luster: Vitreous

Identified May 25, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 8.0 on Mohs scale; Color: Swiss Blue; Luster: Vitreous; Crystal Structure: Orthorhombic; Specific Gravity: 3.49–3.57. Shows perfect basal cleavage.

Formation & geological history

Formed in igneous environments during the late stages of magma cooling, specifically within granite pegmatites and rhyolite cavities. Often found as a primary mineral in association with fluorite and cassiterite.

Uses & applications

Primarily used as a gemstone in high-end jewelry (rings, pendants) and popular for gemstone collectors due to its clarity and hardness.

Geological facts

While naturally blue topaz is extremely rare and usually pale, the vibrant 'Swiss Blue' seen here is typically achieved by irradiating and then heating colorless topaz to create a permanent, deep color change.

Field identification & locations

Identified in the field by its high hardness (it can scratch glass and quartz), high density (it feels heavy for its size), and its characteristic prismatic crystals with vertical striations.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral