Fake Tumbled Smoky Quartz

Irradiated smoky quartz

Irradiated smoky quartz is clear or milky quartz exposed to gamma rays, which do in a short time what natural radiation in granite does over millions of years. Both act on traces of aluminum in the quartz, so the smoke is the same kind of color center either way. The result is still quartz, but its color is man-made, and it should be sold as irradiated or treated. Gamma treatment does not make the stone radioactive. Long sun and strong heat can undo either kind of smoke, so natural and lab-darkened pieces alike should stay off sunny windowsills.

Natural smoky quartz vs irradiated

Natural smoky quartz vs irradiated quartz shows up mostly in color and clarity:

Natural: tea brown, gray brown or charcoal, see-through at thin edges, often unevenly zoned.
Irradiated: an even, inky black or very dark gray, often hazy inside, because the starting stone was often cloudy quartz.
Morion: natural black smoky quartz exists, so black alone proves nothing, though morion can show deep brown at its thinnest edges under a strong light.
Quantity: bags of matching jet black tumbles at a low price are almost always irradiated.

How to spot fake smoky quartz

How to spot fake smoky quartz takes a strong flashlight and a 10x loupe. Shine the light through the thinnest edge of the tumble. Natural smoky quartz glows brown or gray, while irradiated milky quartz tends to glow a murky gray with white clouds inside. Under the loupe, quartz shows angular, wispy or needle-like inclusions, and glass, where light gets through at all, shows round bubbles and curved swirl lines. A tumble with a perfect, even black and no inclusions at all is the one to question.

Glass and obsidian sold as smoky quartz

Glass and obsidian sold as smoky quartz are true fakes, because neither one is quartz. Obsidian is natural volcanic glass, black or smoky gray, sometimes with a gold or silver sheen, and it is softer than quartz at about 5 to 5.5 on the Mohs scale. Apache tears, small rounded nodules of obsidian, look smoky brown against a light and are easy to confuse with smoky quartz tumbles. Man-made black glass gets tumbled into the same smooth pebbles.

Why tumbled smoky quartz is easy to fake

Tumbled smoky quartz is easy to fake because tumbling removes the clues. A raw crystal shows its points, growth lines and color zones; a polished pebble shows only color and clarity. Tumbling also rounds off the thin edges you would use to judge transparency, so hold a tumble up to a strong light, not room light. That is also why so many cheap tumbles are irradiated: low-grade clear and milky quartz is plentiful, and treatment turns it into a darker stone that sells faster.

Smoky quartz points and towers

Smoky quartz points and towers follow the same rules as tumbles, with more stone to look through. Irradiated pieces cut from milky quartz look black with cloudy white patches when a light shines through them, and molded glass points show seams and a too-perfect symmetry. Natural smoky points are usually brown, see-through and unevenly colored.

Smoky quartz labels to trust

Smoky quartz labels to trust say what was done to the stone and where it came from. Look for natural, irradiated or treated on the label, and a real locality such as the Pikes Peak granite of Colorado, Minas Gerais in Brazil or the Swiss Alps. The smoky quartz guide covers the natural stone, and Mindat's smoky quartz page has the mineral data.