Real or fake: spotting an imitation
Most "fake" crystals are one of five things: glass, dyed stone, heat-treated stone sold as a rarer natural colour, reconstituted powder bonded with resin, or plastic. None of the tests below need equipment. Together they catch the large majority of imitations.
Temperature
Real quartz-family stones feel cool when you first pick them up and take a moment to warm. Glass warms almost immediately and quickly matches your hand. Hold the piece to your cheek for a second: cold means stone, room-temperature means glass is likely.
Bubbles
Trapped round bubbles are the clearest sign of glass or resin. Look into the stone under a bright light, turning it. Natural crystal has veils, fractures and mineral inclusions (irregular, angular, wispy) but not perfectly spherical bubbles.
Colour that is too good
Natural colour is uneven: darker in zones, paler elsewhere, sometimes banded. A stone that is one saturated, uniform colour throughout (especially a loud, electric shade) has usually been dyed. Amethyst that is deep purple from tip to base, citrine in a burnt orange, aqua-blue "aura" coatings: all treated.
Dye in the cracks
On dyed stone, colour pools and darkens inside fractures and around the base of points, where the dye soaked in deepest. Run a cotton bud dipped in acetone (nail-polish remover) over an inconspicuous spot; colour coming off on the bud means surface dye.
Hardness
Quartz-family stones (amethyst, citrine, clear and rose quartz, tiger's eye) are hard (around 7 on the Mohs scale) and a steel knife or key will not scratch them; they will scratch glass. Selenite is the opposite: so soft a fingernail marks it. If a "selenite" piece resists a fingernail, it is another white stone.
Weight
Stone is denser than plastic and slightly denser than most glass. A piece that feels surprisingly light for its size is likely plastic or resin. This is a rough feel test, not a measurement, but an obviously light "crystal" is a red flag.
Price and names
If a large, flawless, vivid "natural citrine" or "cherry quartz" or "strawberry quartz" tower costs very little, it is manufactured glass. Trade names that do not name a real mineral (cherry quartz, blue obsidian, opalite, goldstone) are glass by definition, not frauds, but not natural stone either.
Quick tells, stone by stone
| Stone | Real | Usually fake |
|---|---|---|
| Rose Quartz | Muted, cloudy pink, uneven through the stone; cool to the touch at first. | Bright bubblegum pink, glassy-clear, even colour, sometimes with round bubbles inside. |
| Amethyst | Purple deepest at the point tips, paler towards the base; sometimes faint bands; cool and a little heavy. | One flat purple everywhere, very dark, glass-clear, small bubbles; or a bright "aura" sheen coating. |
| Citrine | Soft lemon-to-honey gold, gently coloured; natural citrine is uncommon and never neon. | Burnt orange or amber with a chalky white base (that is heat-treated amethyst), or a uniform glassy yellow (glass). |
| Clear Quartz | Almost always some internal veil, hairline or cloud; stays cool in a warm room. | Flawless, warms fast in the hand, round bubbles under the light. |
| Selenite | Very light for its size, satin fibres that catch the light, soft enough to mark with a fingernail. | Dense, heavy, hard to a fingernail: usually another white stone (howlite, aragonite) sold under the name. |
| Black Tourmaline | Matte to lightly shiny, fine lengthwise grooves like a bundle of rods, dense, brittle edges that flake. | Glossy, perfectly smooth, light: black glass or resin. |
| Tiger's Eye | A band of light that slides across gold-and-brown stripes as you tilt it; natural earth tones. | Electric blue or bright red with the same sheen: dyed. (Natural red tiger's eye exists but is rusty, not scarlet.) |
| Black Obsidian | Smooth, glassy and slightly warm (it is natural volcanic glass), with a faint smoky edge held to light. | Moulded shapes with a seam, or air bubbles; man-made glass rather than obsidian. |
| 7 Chakra Sets | Seven natural stones with everyday variation; the turquoise-blue bead is usually stabilised, which is normal. | All seven glassy, identical bead to bead, unnaturally bright: dyed howlite and glass. |
No home test is conclusive. If it matters (a large or expensive piece), ask the seller for a gemmological lab report, or have the stone tested. See How we choose the stones for how our own material is tested.