How to tell if a moonstone is real
This page lists practical, non-destructive checks you can do at home and explains when to seek professional testing. It covers the key visual clues, simple tools to use, common fakes to watch for, and when lab verification is appropriate.
Published
Quick facts
- Hardness
- 6 to 6.5 on the Mohs scale
- Mineral
- feldspar
What moonstone is
Moonstone is a gemstone in the feldspar mineral group. It usually appears as a translucent to semi-transparent stone with a soft, floating light effect called adularescence. Many moonstones are cut as cabochons to display that sheen.
Key visual signs of a real moonstone
Look for adularescence: a blue, white, or silver sheen that seems to move under the surface when you tilt the stone. Genuine moonstone shows internal layers or fine growth lines rather than uniform color. Surface imperfections and subtle internal cleavage planes are normal. Keep in mind moonstone has a hardness of 6 to 6.5 on the Mohs scale, so it will show wear differently from harder gems such as diamond or corundum.
Tools and simple checks you can do at home
Use a 10x loupe or a magnifier, a neutral white light, and a dark background. Tilt the stone under the light to watch the sheen move independently of surface reflections; that movement indicates adularescence. Inspect the stone for tiny round bubbles—glass imitations often contain visible bubbles. Check the back and sides of cabochons for a clear glue line or abrupt change in material, which suggests a doublet or composite. Avoid any aggressive scratch tests; rely on observation and magnification instead.
Common fakes and how to spot them
Glass and some plastics are common imitations. Glass often shows round gas bubbles and a uniform interior with no layered structure. Resin and plastic may look too lightweight and can have mold marks. Some assembled stones are glued to a backing; examine the meeting line for glue or an abrupt join. Synthetic stones meant to mimic adularescence may show a repeating pattern or an unnaturally even sheen.
When to get professional testing
If the stone is valuable or you need a definitive identification, send it to a qualified gemologist or a gem lab. Professionals use instruments and tests not available at home, and they can confirm natural vs. assembled or treated material. If you want a quick photo-based check before lab testing, you can use Jewelry Identifier.
Common questions
- Can I scratch a moonstone to test it?
- No. Moonstone has a hardness of 6 to 6.5 on the Mohs scale. A scratch test can damage the gem and any setting. Use magnification and light-based checks instead, or seek professional testing.
- How does moonstone differ from labradorite?
- Both are members of the feldspar group, but labradorite shows labradorescence, which tends to be broader and more colorful. Moonstone typically shows a softer white or blue adularescence and is commonly cut as cabochons to display that effect.
- What does a bubble inside a stone indicate?
- A round gas bubble seen under magnification usually indicates glass, not natural moonstone. Natural feldspar growth has irregular inclusions, cleavage planes, or layering rather than perfect round bubbles.