igneous
Labradorite (specifically Larvikite beads)
Plagioclase Feldspar (Na,Ca)(Si,Al)4O8
Hardness: 6.0-6.5 Mohs scale; Color: Gray to black background with blue or silvery flash (labradorescence/Schiller effect); Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in two directions.
- Hardness
- 6
- Luster
- Vitreous to pearly
Identified More igneous →
Explore Labradorite (specifically Larvikite beads) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.0-6.5 Mohs scale; Color: Gray to black background with blue or silvery flash (labradorescence/Schiller effect); Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in two directions.
Formation & geological history
Formed through the crystallization of mafic igneous rocks (anorthosite or monzonite). The optical effect is caused by the exsolution of different feldspar minerals during slow cooling of magma, creating layers that diffract light.
Uses & applications
Primarily used for ornamental purposes, including jewelry (beads, cabochons), interior design (countertops, tiles), and as a popular specimen for crystal collectors.
Geological facts
Labradorite was first discovered on Paul's Island in Labrador, Canada, in 1770. The metallic play of colors is officially known as labradorescence. High-quality versions from Finland are specifically called Spectrolite.
Field identification & locations
Identify by rotating under a light source to find the 'flash' or play of color. In the field, look for dark, crystalline rocks where light glints off specific planes. Common locations include Labrador (Canada), Madagascar, Norway (Larvik), and Finland.
