Labradorite Identification Guide
A practical guide to identifying labradorite by its flashing labradorescence, gray base color, and feldspar cleavage.
Read the full Labradorite encyclopedia entry →
What Labradorite Looks Like
Labradorite is a plagioclase feldspar prized for labradorescence - a flash of metallic-looking color (blue, green, gold, sometimes orange or violet) that sweeps across the surface as you tilt the stone. The base body color is typically smoky gray, dark gray, or near-black, with the iridescence appearing only at certain viewing angles. Luster is vitreous to slightly waxy; the stone is translucent to nearly opaque. Crystals are blocky; rough material often shows flat cleavage planes that carry the color flash.
Step-by-Step Field ID Checklist
- Tilt the stone under a light - look for a single sheet of color (blue/green/gold) that appears and disappears with angle. This labradorescence (schiller) is the master clue.
- Check the base color - dull gray to dark gray, not transparent.
- Find cleavage planes - two good cleavages meeting at about 90 degrees are typical of feldspar.
- Test hardness - should scratch glass but not be scratchable by a steel knife easily.
- Look for the flash on a flat plane, not scattered sparkles (which suggest aventurine or goldstone).
Key Diagnostic Tests
- Labradorescence: Caused by light interference within microscopic lamellar intergrowths; the color is a sheen, not surface stain.
- Mohs hardness: 6-6.5 - scratches glass; a knife will not easily scratch it.
- Cleavage: Two directions at nearly 90 degrees, giving flat reflective surfaces.
- Streak: White.
- Specific gravity: ~2.68-2.72, typical feldspar weight.
- No acid reaction; not magnetic.
Common Look-Alikes and How to Tell Them Apart
- Moonstone: Shows a floating bluish-white adularescence (billowy glow), not a flat metallic color flash; usually pale and more translucent.
- Spectrolite: Simply a high-quality Finnish labradorite with full-spectrum flash - same mineral.
- Larvikite: A rock (monzonite) full of feldspar that shows silvery-blue schiller, but it is a granular rock with multiple minerals, not a single gem.
- Aventurine/goldstone: Show point-like glittery sparkle (aventurescence) from inclusions, not a continuous sheet of color.
- Black moonstone: Gray-to-black with subtle blue adularescence; flash is softer and cloudier than labradorite's sharp schiller.
Where Labradorite Is Found
Labradorite occurs in mafic igneous rocks (anorthosite, gabbro, basalt). Major sources are Labrador and Quebec, Canada (the type locality), Finland (spectrolite), Madagascar (the main gem source today), Norway, Russia, and Ukraine.
Frequently asked questions
How can you tell if it's real labradorite?
Tilt it under light: genuine labradorite shows a flat sheet of blue, green, or gold color (labradorescence) that appears and vanishes with angle, over a gray base. It has feldspar hardness (6-6.5) and two cleavage planes near 90 degrees.
What does labradorite look like?
It is a gray to dark-gray, translucent feldspar that flashes metallic blue, green, or gold when tilted toward the light.
Labradorite vs moonstone - what's the difference?
Moonstone shows a soft, floating blue-white glow (adularescence) that moves smoothly, while labradorite shows a sharper metallic color flash on flat planes and usually has a darker gray body.
Is labradorite the same as spectrolite?
Yes - spectrolite is a trade name for top-grade Finnish labradorite that displays the full spectrum of flash colors; mineralogically it is the same plagioclase feldspar.