Morion

As a variety of smoky quartz, morion forms in the same settings, most characteristically in pockets in igneous rocks and pegmatites. National Museums Scotland notes that natural Scottish quartz ranges from near-black morion stones through browns to yellow citrine.

Morion has the gemological constants of quartz (refractive index 1.544–1.553, specific gravity 2.65). Black or brown quartz crystals coloured by inclusions of minerals or organic matter, such as those embedded in gypsum, anhydrite or limestone, are often wrongly called morion; true smoky quartz and morion can be told apart from them by dichroism. Gem treater Mark Liccini reports that a low dose of cobalt-60 irradiation turns almost all quartz blackish, and that he sold such black irradiated quartz for use as black onyx.

Like other smoky quartz, its colour pales at temperatures above 200–300 °C and with prolonged exposure to UV light, so keep it away from high heat and long exposure to strong sunlight.