Image: <bdi><a href="https://www.wikidata.org/wiki/Q126871365" class="extiw" title="d:Q126871365"><span title="photographer from the United States">Shannon Heinle</span></a></bdi> (CC0)
tricliniccommonSilicates (Feldspar Group, Plagioclase Series)
Labradorite
(Ca,Na)(Si,Al)4O8
Labradorite is known for its striking play of colors, called labradorescence, which ranges from blues and violets to greens, yellows, and oranges. This iridescent effect is visible across cleavage planes and in sliced sections.
Labradorite Physical Properties
Mohs Hardness
6.5Crystal System
triclinicLuster
vitreousStreak Color
whiteCleavage
perfect in two directions (pinacoidal)Fracture
uneven to conchoidalSpecific Gravity
2.7Colors
blue, violet, green, yellow, orange, greyTransparency
translucent to opaqueType Locality
Labrador, CanadaMineral Group
Silicates (Feldspar Group, Plagioclase Series)Uses
jewelry, ornamental stone, collectorAssociated Minerals
pyroxene, amphibole, olivine, magnetiteRarity
commonGeological Context
Labradorite is a plagioclase feldspar that forms in mafic igneous rocks such as gabbro, basalt, and anorthosite. The labradorescence is caused by light interference from microscopic lamellar intergrowths of different plagioclase compositions within the crystal.
