£1.50 – £4.50
Anorthosite phaneratic igneous rock speicmens of Protozoic age from Hellvik in Norway. The samples have an almost pure white colouration due to an abundance of plagioclase feldspar which comprises of most of the rock and exhibit a coarse grain size with visible with the naked eye and exhibiting a low density. The samples are suitable for the more serious or professional collector as well as higher level educational use and are available in three sizes and supplied in a card tray with a label.
Anorthosite is an intrusive igneous rock which is of great importance to the geological and scientific community as they are currently not fully understood and have also been found in lunar (Moon) rocks. The rock its self is phaneratic, with crystal structures visible with the naked eye and is composed almost entirely of plagioclase feldspar of coarse grain size, approximately over 90% with only minor amounts of mafic minerals such as pyroxenes, magnetites and olivine. It is currently understood that, due to plagioclase being a less dense mineral than the rest of magma, they 'float' top the top of an igneous body and crystallise at the top of a magma chamber in large concentrations. These samples come from Hellvik in Norway and are estimated to be Proterozoic in age, ideal for serious collectors and high level educational use, the samples are available in three sizes and come supplied in a card tray with an information label.