Q: Hi there, how do I measure a gemstone with a ruler? I have gorgeous white zircon gemstones, round, but I don't know how to measure, thanks
A: Hi Roger! I'm glad you asked this question. A lot of people new to jewelry making and gemstones reach for their desk ruler when they want to measure a stone, but the short answer is that you cannot measure a stone accurately using an ordinary ruler. You need a millimeter gauge. You can buy fancy digital gauges but I find that a simple brass millimeter gauge serves the purpose and is inexpensive. I have a tutorial on how to use a brass millimeter gauge. Just copy and paste this link into your browser. Always measure the depth of the stone as well as the length and width.