Started collecting crystals a while back and got burned more than once — dyed agate sold as "natural amethyst," glass passed off as quartz, resin "raw" specimens that were basically plastic with glitter.

Here's the cheapest test that catches 80% of fakes before you even need a loupe:

1. Temperature test — Real crystals feel cold and stay cool longer than glass or resin when you hold them. Fakes warm up to your hand temp almost instantly.

2. Color consistency — Natural crystals have uneven, streaky color from mineral inclusions. Dyed fakes have suspiciously uniform, saturated color — especially in cracks and pits where dye pools.

3. Weight check — Glass is noticeably lighter than most quartz/amethyst of the same size. Get a feel for real specimens and fakes start standing out immediately.

4. Bubble check — Hold it to a light. Glass and resin often have tiny air bubbles trapped inside. Real crystal inclusions look like cracks, feathers, or mineral veils — not perfectly round bubbles.

None of these are 100% foolproof alone, but stack 2-3 of them and you'll catch almost every common fake sold on marketplaces.

Building a small community for people just getting into collecting who want to get good at this fast — happy to look at photos and help ID pieces if anyone's unsure about something they bought or are about to buy.