However, some other non-mineral rocks (such as lapis lazuli) or organic materials can also be also used for jewelry and are called gemstones. These include amber or jet. Pearls and coral are sometimes also called gemstones.
Being rare or in short supply also makes a gemstone valuable.
The Ancient Greeks began to decide which gems are precious and semi-precious. This continued in other cultures.
Other websites change
- "Book of Royal Gemstones" is a book from 1554 that talks about gemstones.
- "The Blossoms of Thoughts Regarding the Precious Stones" is an old book from the 1600s that is considered one of the most important books about precious stones. It is written in the Arabic language.