Large crystals found in geodes and other rocks are relatively rare. Pink ChalcedonyA pink chalcedony shows off its beauty. Chalcedonies include many types of cryptocrystalline quartz gems and ...

The rarest gemstone in the world is considered to be ... of 5.5. It formed deep underground in a pegmatite — an igneous rock. Its chemical formula is Bi³⁺Sb⁵⁺O₄ with traces of tantalum.

Evidence for the use of rock crystal - a rare type of perfectly transparent quartz which forms in large hexagonal gems - has occasionally been found at prehistoric sites in the British Isles, but ...

It was around 5:30 a.m. Friday when the two men broke into Kelowna’s Rocks and Gems Store. The owners believe they were targeting a rare geode from Brazil, estimated between $2,500 and $3,000.