Quick answer

Real amethyst usually shows uneven color, with lighter and darker purple zones and deeper color near the tips of points. It has a hardness of 7, so it scratches glass, and it often contains small natural inclusions. Perfectly even color, round bubbles or a stone that will not scratch glass suggest glass or resin. Synthetic amethyst is real quartz grown in a lab and usually needs a gem lab to identify.

Quick checks for real amethyst

  • Color zoning: lighter and darker purple areas rather than one flat color.
  • Inclusions: tiny cracks, clouds or crystals inside, not round bubbles.
  • Hardness: it scratches glass.
  • Temperature: it feels cool and stays cool in your hand.
  • Shape: raw amethyst grows as six-sided quartz points, often in clusters or geodes.

1. Look at the color zoning

Natural amethyst rarely forms one even shade. Look through the stone toward a window. You will usually see bands, patches or V-shaped chevrons of darker and lighter purple, and points are often darkest at the tip and paler toward the base. Geology.com notes that strong color zoning is very common in natural amethyst and not usually seen in synthetic amethyst.

Faceted gems are cut to hide zoning, so a pale or even area is not proof of a fake on its own. Combine this check with the others.

2. Check inside with a magnifier

Use a 10x loupe or your phone's zoom. Natural amethyst often shows small fractures, feathery inclusions or clouds. Round gas bubbles and swirl lines point to glass. A completely flawless, deeply colored stone at a low price deserves suspicion.

3. Do a scratch test

On a hidden spot, try to scratch a piece of glass with the amethyst. Real amethyst, at 7 on the Mohs scale, leaves a scratch. Glass and resin imitations will not. Never test a stone you plan to sell, and never scratch the amethyst itself with something harder.

4. Feel the temperature and weight

Quartz conducts heat away from your skin, so amethyst feels cool and stays cool longer than glass. Resin and plastic feel warm and light. Amethyst has the same weight as any quartz of its size, so a piece that feels noticeably light is suspicious.

5. Inspect clusters and geodes

Raw clusters and geodes are rarely glass, but they can be altered. Check for glued points at the base, paint or dye on the outer rind, and color that looks painted on rather than inside the crystals. Bright orange "citrine" geodes are usually amethyst that has been heated, as GIA notes for most citrine on the market.

6. Know when you need a lab

Synthetic amethyst is real quartz grown in a lab and passes every home test. Gemologists separate it from natural amethyst using inclusions and growth features visible under a microscope. If you are paying for a large, clean, deeply colored gem, ask for a lab report.

What affects amethyst value

Most tumbled amethyst, small points and clusters are inexpensive because amethyst is common. Price rises with deep, even purple color with red or blue flashes, clarity, size and the quality of the cut. Large decorative geodes are priced by size, color and how complete the crystal lining is.

Check your amethyst with a photo

Upload a photo to the free crystal identifier to confirm the stone is amethyst and see the look-alikes and fakes to rule out. For the checks that apply to every stone, read how to tell if a crystal is real.

Frequently asked questions

Does real amethyst have even color?

Usually not. Natural amethyst tends to show zones of lighter and darker purple, often in bands or V-shaped patterns, with the deepest color near the tips. Perfectly even color is common in glass and in synthetic amethyst.

Can glass scratch amethyst?

No. Amethyst is quartz with a hardness of 7, and window glass is about 5.5. Real amethyst scratches glass, while glass leaves no mark on amethyst.

Is synthetic amethyst fake?

Synthetic amethyst is real quartz grown in a laboratory, with the same chemistry and hardness as natural amethyst. It is not glass, but it is worth less than natural amethyst and should be labeled as lab-grown. A gem lab can usually tell them apart.

Why is my amethyst turning pale?

Amethyst color can fade with long exposure to strong sunlight or heat. Keep it out of sunny windowsills and away from heat sources.

Sources and further reading

The references we used to prepare this guide.