igneous
Labradorite (a variety of Anorthosite or Plagioclase)
Labradorite (member of Plagioclase Feldspar series), (Ca,Na)(Al,Si)4O8
Hardness: 6–6.5 on Mohs scale. Color: Dark gray to black body color with 'labradorescence' (iridescent flashes of blue, green, or gold). Luster: Vitreous to pearly. Crystal structure: Triclinic. Cleavage: Perfect in two directions.
- Hardness
- 6–6
- Luster
- Vitreous to pearly
Identified More igneous →
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Physical properties
Hardness: 6–6.5 on Mohs scale. Color: Dark gray to black body color with 'labradorescence' (iridescent flashes of blue, green, or gold). Luster: Vitreous to pearly. Crystal structure: Triclinic. Cleavage: Perfect in two directions.
Formation & geological history
Formed in mafic igneous rocks such as basalt or gabbro through the slow cooling of magma. The characteristic 'schiller' effect or play of color is caused by sub-microscopic exsolution lamellae (layers) of different feldspar compositions within the stone, which diffract light.
Uses & applications
Predominantly used as a gemstone for jewelry, ornamental carvings, and high-end architectural materials (countertops or wall tiles). It is also highly valued by mineral collectors for its unique optical properties.
Geological facts
Labradorite was first discovered in 1770 on Paul’s Island in Labrador, Canada. Inuit legends claim that the Aurora Borealis was once trapped inside the rocks of Labrador and was released by a warrior striking them with a spear, leaving some of the light behind in the stones.
Field identification & locations
Identify in the field by its dark body color and rotating the specimen under a light source to find the characteristic 'flash' of color. Common locations include Canada (Labrador), Madagascar, Finland (known as Spectrolite), and Russia.
