Olivine

Miners have found irregularly shaped olivine nodules (round rocks containing olivine crystals) in some lava flows in the United States,China and Vietnam. Very rarely, large crystals can be found in the veins and caverns of certain types of solidified lava.

Geologists believe these two types of deposits are related to seafloor spreading. When the earth’s crust breaks up,

mantle rock is pushed up to the surface and seafloor spreading is formed. At some point, these rocks can change, deform, and become part of the mountains in later crustal movements (as happened in Myanmar).

Olivine is a gem-grade variety of the mineral olivine. Its chemical composition includes iron and magnesium, and iron is responsible for the yellow-green color.The gemstone is usually found in a type of volcanic rock called basalt, which contains both elements.