Olivine–pigeoniteLow-Ca clinopyroxene, (Ca,Mg,Fe)SiO3, found as a major mineral in eucrites and shergottites. In order to be considered pigeonite, the clinopyroxene must contain 5 to 20 mol % of calcium (Wo5 - 20). Chondrites of petrologic types 4 and below contain significant low-Ca clinopyroxene. During metamorphism to higher temperatures, all existing
19° 55′ N., 56° 15′ E. A single stone weighing 596 g was found during oil prospecting in the Hajmah area (formerly known as the Haima oil bore) in Oman before 1958. This ureilite is distinct from two L chondritesChondrites are the most common meteorites accounting for ~84% of falls. Chondrites are comprised mostly of Fe- and Mg-bearing silicate minerals (found in both chondrules and fine grained matrix), reduced Fe/Ni metal (found in various states like large blebs, small grains and/or even chondrule rims), and various refractory inclusions (such Click on Term to Read More found in the same area at that time designated Hajmah (b) and (c). Current models of ureilite formation are presented on the Kenna page.