Hundreds of 'Rock Crystals' Found From a 6000-Yr-Old Site Indicate Quartz Fragments Were Used to Decorate Graves The burial practices of ancient populations have always intrigued researchers because ...

the rock broke open, revealing yellow crystals of elemental sulfur: brimstone. Although sulfates are fairly common on Mars, ...

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 ...

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 ...