The mineral journal

Every year people carry home a pocketful of what they're sure is gold. Here are the tests that settle it, in order of how much they cost you, and the one that gives a false answer in Britain.

Some minerals genuinely need careful handling. Most of the ones people worry about don't. Here's how to tell the difference, and why the route into your body matters more than what's on the label.

It sounds like it should have one answer, and almost every page online gives you one: millions of years. It's the line that ends up in product descriptions, because a big number sounds impressive. The trouble is that it's wrong...

Amethyst is chemically identical to clear quartz, so why is it purple? The answer involves trace iron and natural radiation buried in the ground. Here's the real science, in plain terms.

Some of the prettiest "crystals" on the market are actually manufactured glass. Here's the truth about cherry quartz, goldstone and opalite, and how to spot glass.

Most inexpensive "turquoise" isn't turquoise at all; it's dyed howlite or magnesite. Here's how to spot the impostors, including the simple acetone test that catches them.