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.

Quartz stones are semi-precious gems found in various colors, known for their beauty and energetic properties. Throughout history, different cultures have valued quartz for its healing ...

A member of the quartz family, amethysts with intense ... Here is how these factors play into the price of this precious gem.