The name labradorite comes from the Labrador region of Canada, where it was found around 1770.
After a new source was found in Finland in the forties, labradorite was introduced in the gem market under the name spectrolite.
Labradorite is sometimes called rainbow moonstone, term which is now prohibited.
Like moonstone, this white to dark gray stone, exhibits a colored effect. But, unlike moonstone, this effect called labradorescence is visible only when rotated at an angle, and appears through the entire surface of the stone.
Labradorescence is caused by light interference through the thin plates resulting from repeated twinning, characteristic to the structure of labradorite.
Large slabs of low quality labradorite are used as facing material in construction building.
Labradorite occasionally occurs in transparent pale yellow color, but this collector material is fragile and does not show labradorescence.