Crystal Authentication Field Guide

Dyed quartz, glass, synthetic amethyst.

Natural amethyst shows color zoning (lighter and darker patches) when held to light. Fakes are uniformly saturated. Dyed pieces show concentrated color in cracks under 10x magnification.

Heat-treated amethyst sold as natural citrine.

Natural citrine has a pale yellow to smoky yellow color. Heat-treated amethyst is a vivid orange-yellow with white bases on points (amethyst matrix showing through). Nearly all 'citrine' on the market is heat-treated amethyst.

Dyed howlite, dyed magnesite, reconstituted turquoise, plastic, stabilized turquoise sold as natural.

Real turquoise has irregular matrix patterns (black or brown veining). Dyed howlite shows color pooling in the veins under magnification. Plastic warms in hand quickly.

Green bottle glass cast in moldavite-like shapes.

Real moldavite has characteristic textured surface with bubbles and grooves from rapid cooling. Fake moldavite is smooth and has regular bubble patterns under magnification.

Resin with malachite-green pigment, dyed howlite.

Real malachite is heavy and cool. Run a needle across an inconspicuous spot: real malachite resists scratching (Mohs ~4) but resin scratches easily. Real malachite has concentric ring banding with varying light and dark greens.

Opalite (glass), resin composites, doublets, triplets.

Real opal shows play-of-color that shifts as you rotate the stone. Opalite is a milky glass that glows when backlit but does not flash spectral colors. Doublets have a clear seam visible from the side under magnification.

Plastic pearls, glass pearls, shell pearls.

The tooth test. Real pearls feel gritty when lightly rubbed against the edge of your teeth. Fake pearls feel smooth. Real pearls also have slight surface irregularities under magnification; fakes look perfectly uniform.

Dyed jasper, dyed howlite, resin composites.

Real lapis has gold or brass-colored pyrite inclusions. Dyed stones sometimes have fake pyrite-like specks that look painted on. Acetone on a cotton swab will remove dye from fake lapis (test an inconspicuous spot).

Pink glass, dyed quartz.

Real rose quartz has subtle internal cloudiness and pale pink color with variations across the piece. Glass fakes are often too clear or too uniformly pink. A strand of 'rose quartz' with identically saturated beads is suspicious.

Glass, synthetic quartz, leaded crystal.

Natural quartz often contains small internal inclusions or veils. Glass is too clear, or has bubbles if poor quality. Quartz is cool to the touch; glass warms faster.

Green glass, dyed beryl, synthetic emeralds, green cubic zirconia.

Real emeralds almost always have visible inclusions (jardin). A flawless emerald is either lab-grown or not an emerald. Under a jeweler's loupe, natural emerald inclusions look like internal cracks or wispy clouds.

Glass-filled corundum, synthetic ruby, garnet, red spinel.

Real ruby has silk-like inclusions under magnification. Glass-filled rubies show gas bubbles at the filled fractures. Garnet lacks ruby's fluorescence under UV light.

Dyed serpentine, dyed quartzite, plastic, glass.

Real jade is surprisingly dense and cool. Tap two pieces together: real jade makes a clean, clear ringing sound. Plastic makes a dull click. Dyed jade shows color concentrated at the surface under magnification.

Black glass.

Tricky because real obsidian IS volcanic glass. Distinguish by checking for conchoidal fracture patterns (curved, shell-like breaks) and natural inclusions. Snowflake obsidian should have actual cristobalite crystal patterns, not printed or painted flecks.

Fiber optic glass (also called 'cat's eye glass').

Real tiger's eye has organic, slightly wavy golden fiber patterns. Fiber optic glass has perfectly straight, uniform fibers. Real tiger's eye also has color variations across the stone.

Dyed chalcedony, blue plastic, resin composites.

Real larimar only comes from the Dominican Republic and has soft, cloud-like blue and white patterns. Dyed fakes have harsh color transitions. Real larimar is slightly translucent at thin edges.

Dyed howlite, purple jasper, plastic.

Real sugilite has a distinctive purple-pink color with visible mineral texture. Dyed alternatives are too uniform in color. Real sugilite is rare and expensive; most 'sugilite' under $50 is fake.

Black glass, coal, dyed stones.

Real shungite contains carbon and conducts electricity (you can test this with a multimeter). Elite (noble) shungite has a silvery metallic sheen. Regular shungite is matte black. Fakes fail the conductivity test.

Synthetic labradorite (spectrolite glass), dyed pieces.

Real labradorite shows labradorescence (spectral color flash) at specific angles. The flash should shift as you rotate the stone. Synthetic versions often have too uniform or rainbow-like flash patterns.

Alabaster, resin.

Real selenite has a fibrous, silky surface and is soft enough to scratch with a fingernail (Mohs 2). It should feel warmer than denser stones. Alabaster feels heavier. Resin warms to the touch very quickly.