Science, tools, identification, treatment, valuation & grading of gems
Science, identification, classification, and testing of minerals
Gemstone jewelry settings, metals, tools, cutting & faceting stones
List of all gemstones from A-Z with in-depth information for each
Thousands of gem photos searchable by various properties.
Everything you need to know about buying your perfect diamond
Learn more about these popular gemstones, their meaning & about buying birthstone jewelry
Price guidance on over 70 types of gemstones
In-depth guides to quality factors of the 40 most popular gemstones
Obsidian is the most common form of natural glass and occurs in many attractive varieties. Since prehistoric times, people have used this material to make jewelry and carvings as well as practical objects, like knives.