Quick answer
A real crystal usually feels cool and stays cool, shows irregular inclusions rather than round bubbles, and has the hardness of the mineral it claims to be. Glass and resin fail one or more of those checks. Dyed and heat-treated stones are real minerals with altered color, so look for dye pooling in cracks and colors that look too even or too bright.
What "fake" usually means
Most fake crystals fall into four groups. Glass and resin imitate a mineral entirely. Dyed stones are real but colored artificially. Treated stones, such as heated amethyst sold as citrine or metal-coated aura quartz, are real minerals whose color was changed. Lab-grown stones have the same chemistry as natural ones and usually need a lab to detect.
Treated and lab-grown stones are not a problem when the seller says so. The problem is a stone sold as something it is not, at a price it does not deserve.
Common fakes and how to spot them
| Sold as | Often actually | How to spot it |
|---|---|---|
| Citrine, deep orange | Heat-treated amethyst | Burnt orange tips fading to a white base; natural citrine is pale yellow to smoky gold |
| Clear quartz sphere | Glass | Round bubbles, swirl lines, flawless clarity at a low price |
| Turquoise, bright and cheap | Dyed howlite or magnesite | Dye pooled in cracks and grey veins; color may rub off on a damp cotton pad |
| Agate in neon pink, blue or purple | Dyed agate | Saturated color concentrated in the bands |
| Cherry quartz, strawberry quartz | Colored glass | Even swirls and bubbles, identical pieces |
| Opal or moonstone with a blue glow | Opalite (man-made glass) | Glows blue on dark backgrounds and orange on light ones |
| Aura quartz | Quartz coated with metal vapor | Oily rainbow film that can scratch off; fine if labeled as coated |
| Malachite, light and flawless | Resin or plastic | Feels warm and light, bands look printed, mold lines |
| Hematite beads that stick to magnets | Synthetic magnetic hematite | Natural hematite is only weakly magnetic |
| Moldavite, bright and cheap | Green glass | Too clear and uniform; real moldavite has a deeply sculpted surface |
1. Feel the temperature
Hold the stone against your cheek or wrist. Quartz and most natural crystals feel cool and stay cool for a while because they move heat away from your skin. Glass warms up faster. Resin and plastic feel warm almost immediately.
2. Look for bubbles with a magnifier
Use a 10x loupe or the zoom on your phone camera. Perfectly round gas bubbles and curved swirl lines are typical of glass. Natural quartz usually shows irregular inclusions instead: cracks with rainbows, clouds, needles or tiny crystals of other minerals.
4. Check for dye
Dye collects where the stone is porous. Look for darker color in cracks, pits and along the edges of bands. Rub a hidden spot with a cotton pad dampened with acetone or nail polish remover. Color on the pad means dye. Skip this test on stones that are already polished and valuable.
5. Judge the color
Natural color is rarely perfectly even. Amethyst shows zones of lighter and darker purple, and natural citrine is pale. Colors that look neon, perfectly uniform or identical across a whole tray of stones deserve a second look.
6. Feel the weight
Resin and plastic feel too light for their size. Pyrite and hematite feel unusually heavy, so a light "pyrite" cube is a red flag.
7. Ask the seller the right questions
- Where was it mined? A specific locality is a good sign.
- Has it been heated, dyed, coated or stabilized?
- Is it natural, lab-grown or glass?
- Can you return it if a gemologist disagrees?
Use a photo as a first check
Upload a photo to the free crystal identifier before you pay. It names the likely stone, flags common fakes and treatments for it, and lists the look-alikes worth ruling out. For an expensive stone, follow up with a gemologist.
Frequently asked questions
How can you tell if a crystal is real or glass?
Look for round gas bubbles and swirl lines under a magnifier, which point to glass. Real quartz has a hardness of 7 and scratches glass, while glass cannot scratch quartz. Quartz also stays cool in your hand longer than glass.
Are dyed crystals fake?
They are real minerals with artificial color. Dyed agate, dyed howlite sold as turquoise and dyed quartz are common. They are fine to buy if the seller labels them honestly and prices them as dyed.
Is opalite a real crystal?
No. Opalite is a man-made glass with a milky blue and orange glow. It is fine as long as it is sold as opalite or glass rather than as natural opal or moonstone.
Can a photo tell if my crystal is real?
A photo can flag likely glass, dye and heat treatment, which is how the free crystal identifier helps. It cannot prove a stone is natural. Only a gem lab can certify that.
Sources and further reading
The references we used to prepare this guide.
