Panguite

panguite

davisite

olivine

troilite

Images

Formula: (Ti,Al,Sc,Mg,Zr,Ca)1.8O3
Oxide, titanium-, scandium- and zirconium- bearing mineral
Crystal System: Orthorhombic
Specific gravity: 3.746 calculated for the empirical formula
Luminescence: Not fluorescent under UV or under the electron beam of a scanning electron microscope
Environments

Meteorites

Although it is fairly recently (in 2010) identified as a "new" mineral, panguite is one of the oldest minerals in the Solar System. It has been found in the Allende, Murchison, and SaU 290 meteorites, and is most likely widespread in carbonaceous chondrites. Associated minerals include titanium-rich davisite, scandium-titanium-rich diopside, olivine and troilite.
The name is for Pan Gu (盤古), a primordial being and creation figure in Chinese mythology and in Taoism. According to legend, Pangu separated heaven and earth, and his body later became geographic features such as mountains and flowing water. The mineral name is in allusion to the ultra-refractory origin of panguite, being among the first solid materials in the Solar System (HOM, Wiki).

Localities

The type locality, the Allende meteorite, Pueblito de Allende, Chihuahua, Mexico, is a carbonaceous chondrite. Panguite was found within one irregular ultra-refractory inclusion in one polished section prepared from a ∼1 cm diameter Allende fragment. The host refractory inclusion is about 30 × 20 µm in size in the section plane and resides within an amoeboid olivine inclusion (AOI), surrounded by a matrix of mostly fine-grained olivine and troilite. Panguite occurs with titanium-rich davisite and minor scandium-titanium-bearing diopside in the refractory inclusion. Davisite appears to be the common thread for panguite. This phase has been observed in two additional inclusions, one from Allende and the other from the CM chondrite Murchison. In both cases, panguite is invariably in contact with davisite. Panguite has also been reported in contact with davisite in a sample from the CH chondrite SaU 290. Given the occurrence in multiple meteorites of variable type (CH, CM, CV), it is concluded that panguite is a rare but widespread constituent of carbonaceous chondrites and, given the consistent association with davisite, it is concluded that the origin of panguite is intimately connected to the origin and evolution of davisite.
Panguite occurs as irregular to subhedral grains, 500 nm to 1.8 µm in size. In section, panguite is opaque (AM 97.7.1219-1225).

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