Schreibersite
An iron–nickel phosphide found in almost all iron meteorites, and a possible source of phosphorus for early life.
Key facts
- Formula
- (Fe,Ni)3P
- Family
- Phosphides, carbides, nitrides and silicides
- Crystal system
- Tetragonal
- First described
- iron meteorites (named 1847)
Schreibersite was named in 1847 by Wilhelm Haidinger after Carl von Schreibers, director of the imperial natural history collection in Vienna, from iron meteorites. It is very rare in Earth rocks.
What it is
Schreibersite is a compound of iron and nickel with phosphorus. It is hard and brittle, harder than the surrounding metal. In iron meteorites it often forms large plates and envelopes around troilite nodules, and tiny needles called rhabdite.
Where it is found
It occurs in nearly every iron meteorite, in pallasites and mesosiderites, and as small grains in enstatite chondrites and ordinary chondrites. The Curiosity rover detected the chemical signature of iron, nickel and phosphorus in an iron meteorite on Mars.
When schreibersite reacts with water it releases forms of phosphorus that dissolve easily and can join organic molecules. Some scientists have suggested that meteorites delivered much of the reactive phosphorus that early life needed.
How it is recognised
On etched slices of iron meteorites, schreibersite stands out as bright, raised, pale bronze plates that resist the acid. It is magnetic and often breaks cleanly. Needle-like rhabdites appear as tiny bright specks in kamacite.
Did you know?
Cutting through schreibersite blunts saw blades, so preparers of iron meteorites know it well.
Rhabdite needles can be so small and numerous that they make kamacite look speckled.