Osbornite
Titanium nitride, golden cubes found in enstatite meteorites and in comet dust.
Key facts
- Formula
- TiN
- Family
- Phosphides, carbides, nitrides and silicides
- Crystal system
- Cubic
- First described
- the Bustee aubrite, 1870
Osbornite was described in 1870 by Nevil Story-Maskelyne from the Bustee aubrite, in the same study that described oldhamite. It is known on Earth only from a few unusual rocks.
What it is
Osbornite is a compound of titanium and nitrogen, extremely hard and with a high melting point. It forms at high temperatures where nitrogen is available and oxygen scarce.
Where it is found
It occurs as tiny golden crystals in aubrites and enstatite chondrites and in some CAIs of CH and CB chondrites. A calcium-aluminium-rich particle from comet Wild 2, returned by Stardust, contains osbornite, showing that it formed at high temperatures near the Sun before being carried to the comet-forming region.
How it is recognised
It forms bright golden-yellow cubes or octahedra in polished section.
Did you know?
Titanium nitride is used to coat drill bits and gives them a gold colour.
The Stardust particle containing osbornite was nicknamed Inti, after the Inca sun god.