How to Tell if Amethyst is Real?

What real amethyst looks like

Real amethyst looks like quartz in every way except the color: glassy luster, six-sided points, a hardness of 7 on the Mohs scale and a purple that sits unevenly in the crystal. The color comes from traces of iron plus natural radiation, and in clusters it is usually strongest at the tips of the points. Amethyst from Brazil, Uruguay, Zambia or Thunder Bay in Canada runs from pale lilac to deep grape, but the checks below work on all of it. Our amethyst guide covers the mineral, and GIA's amethyst page covers it as a gem.

Real amethyst color zoning

Real amethyst color zoning is the best free test you have. Natural amethyst grows in layers, so the purple sits in bands, patches or angular zones, often darker at the tips and paler toward the base. Hold a piece up to daylight and turn it slowly; in faceted stones the zones can show as straight, angled stripes. Glass shows one flat, even shade from end to end, and a perfectly even color in a cheap stone deserves a closer look.

Fake amethyst: glass, plastic and dye

Fake amethyst is usually purple glass, sometimes plastic or resin, and sometimes a cheaper stone dyed purple. Each one leaves clues:

Glass: round bubbles and curved swirl lines under a 10x loupe, plus mold seams on points and beads.
Plastic and resin: light in the hand, warm to the touch and easy to scratch.
Dyed stone: purple pooled in cracks or around drill holes, or color that comes off on a damp white cloth.
Dyed agate: neon violet slices and geodes are agate soaked in dye, not amethyst.

Lab grown amethyst

Lab grown amethyst is real quartz grown in a factory, with the same chemistry and hardness as the natural stone. It shows up mostly in faceted gems and beads, where separating it from natural amethyst can take a gem lab, and rarely in raw clusters and geodes, which cost less to mine than to grow. A flawless, perfectly even stone at a bargain price is the warning sign. Honest sellers label it synthetic or lab created.

Heated amethyst and green amethyst

Heated amethyst turns paler, yellow or even green, and all of it is still real quartz. Heat is how most citrine on the market is made, and the green version is sold as prasiolite or green amethyst. Neither is a fake, but both should be labeled as heated, and neither should be priced like a rare natural stone.

Stones mistaken for amethyst

Stones mistaken for amethyst are real minerals in their own right, just not quartz:

Purple fluorite: much softer (Mohs 4), often in cubes, with flat cleavage planes and strong color bands.
Lepidolite: lilac mica in sparkly, flaky masses that peel in thin sheets.
Charoite and sugilite: opaque purple stones, swirled or massive, that come as solid rock rather than clear points.
Kunzite: pink to lilac spodumene in long, striated blades with strong cleavage.

Home tests for real amethyst

Home tests for real amethyst should stay gentle. A loupe and daylight do most of the work. Quartz feels cool and stays cool longer than plastic, though not much longer than glass, so treat touch as a hint rather than proof. A scratch test works because amethyst (Mohs 7) scratches window glass (about 5.5), but it can mark both, so use it only on a hidden, rough spot of a piece you own. Skip tests with flames, acid or boiling water: they prove little, and heat can fade or crack amethyst.