Some gemstones are also minerals, such as that classic rock diamond, but there are some gemstones that aren’t classed as minerals. A fancy example is pearl, a popular choice in the jewelry industry.

Photograph by blickwinkel/Alamy Rocks themselves are made of clusters ... but with a different arrangement—explaining why diamond is the hardest mineral and graphite (used in pencil lead ...

Scientists estimated that the mineral formed 105 miles beneath the Earth’s surface. A single grain of rock lodged in a diamond contains a never-before-found mineral. And that newfound substance ...

If diamonds are a girl's best friend and you can't afford ... Gemologists will welcome this addition to their libraries." Rocks and Minerals Magazine "...provide[s] a well-illustrated overview....the ...