Labradorite
Last updated: April 2026
Displays a spectacular iridescent effect known as labradorescence.
Labradorite has a specific gravity of 2.70 and a refractive index of 1.559–1.573, with a Mohs hardness of 6.0–6.5. It is biaxial −.
Physical & Optical Properties
RI Range1.559–1.573
SG Range2.68–2.75
SG Typical2.70
Hardness (Mohs)6–6.5
Crystal SystemTriclinic
Optic CharacterDR Biaxial (−)
Birefringence0.011
Dispersion0.012
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterInert
PleochroismWeak
ColorsMulti, Brown, Black, Blue Violet
SpeciesFeldspar
VarietyPlagioclase
Related: Feldspar Varieties
Key Differentiators
- Labradorescence
- Plagioclase twinning lines
- Aggregate appearance
Treatments
- Copper Diffusion (creates red/orange color)
Price Context
Natural — low ($/ct)$5
Natural — high ($/ct)$50
NotePer carat; value depends heavily on strength and color range of labradorescence
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
Measurement Guides
Identifying a labradorite? GemID walks through these tests in order — RI, SG, fluorescence, and more.
Try GemID Free →Studying for the GIA, FGA, or FEEG practical? Labradorite is one of the 130 species in GemID’s drill and exam pool — practice identifying it from its measured properties under timed exam conditions.
Practice exams →