Chalcedonies include many types of cryptocrystalline quartz gems and feature a number of different colors. Geologists can tell a chalcedony from the arrangement and structure of its crystals.

Crystals and gemstones can be more than just beautiful—they can be deadly. Minerals like arsenopyrite, cinnabar, galena, and torbernite carry toxic substances like arsenic, mercury, lead ...

When we talk about crystals around here, we’re generally talking about the quartz variety used to make oscillators more stable, or perhaps ruby crystals used to make a laser. We hardly ever talk ...

Take a walk down the mineralogy collection of any good natural history museum and your face will be aglow with the sparkle of minerals, crystals, and gemstones – but what’s the difference ...

You can also buy a bucket and look for gems. But panning for gold is still ... This pay-to-dig mine is more expensive than ...