World Class Gems explains birthstones and gemstones in plain English: what each stone is, its colors, where it comes from, how hard it is and how to look after it.
Where our facts come from
- Hardness, toughness, stability, cleaning and treatments: the Gemological Institute of America (GIA) care and cleaning guide for each gem.
- What each gem is, colors, sources, history and name origins: the American Gem Society (AGS) birthstone guides.
- The month by month list: GIA and AGS. History of the US list: published accounts of the 1912 adoption and later changes.
Every gem page links to the exact sources it uses. If a source does not cover something, we leave it out rather than guess. "Meanings" are presented as history and folklore, not as claims about what a stone can do.
How often we check
Our facts were last checked on October 16, 2026. We review them at least once a year and whenever GIA or AGS update their guides.
Photos
Gem photos come from Wikimedia Commons under free licenses and are credited on each page. Where we have no suitable photo, we show an illustration.
Contact
Spotted a mistake? Email gems@worldclassgems.com.