It used to take the Earth 3 billion years, 2,000-degree temperatures, a little carbon and a lot of pressure to grow a diamond. Now, a new machine can do it in five days.

“As materials’ cost balloon the way they have these past couple of weeks … I can’t continue to sell them at the prices that I was before,” said Isabel Dennis at KIMA Jewelry.

Even the pros have trouble with certain pieces of jewelry. But there’s at least one reliable way to verify what you’re buying.