How can you tell if a gemstone is fake?

Fake gemstones often give themselves away in a strange way, like having interiors that look too perfect, with an even, uniform colour spread, tiny round gas bubbles sealed in, or a touch that feels noticeably warm, not that usual cold sensation you get from natural stone.

Glass and plastic simulants typically do not share the thermal conductivity of real minerals, so they feel warm quickly, and they also fog fast when you breathe near them. When you look closer with magnification, synthetic stones may display curved growth lines, or they may miss those irregular crystal specks that are common in gems mined from the earth.