Tsangpoite
A calcium phosphate silicate from the D'Orbigny angrite, one of the oldest igneous rocks known.
Key facts
- Formula
- Ca5(PO4)2(SiO4)
- Family
- Phosphates
- Crystal system
- Hexagonal
- First described
- the D'Orbigny angrite, 2018
Tsangpoite was described in 2018 from the D'Orbigny angrite, found in Argentina in 1979. It is known only from meteorites.
What it is
Tsangpoite is a calcium phosphate in which a silicate group replaces part of the phosphate. It is the hexagonal form of a compound otherwise known as silicocarnotite. Minerals like it hold phosphorus, a vital element for life, in igneous rocks.
Where it is found
It occurs at grain boundaries in D'Orbigny with matyhite, kuratite, ulvöspinel, iron sulphide and iron-rich olivine. It may have crystallised from the last drops of melt, or grown when a fluid reacted with the rock.
How it is recognised
It is identified by microprobe analysis and electron backscatter diffraction.
Did you know?
D'Orbigny crystallised about 4,564 million years ago, within a few million years of the Solar System's birth.
Angrites are named after Angra dos Reis, a stone that fell in Brazil in 1869.