Adrianite
A chlorine-rich silicate that replaced primary minerals in an Allende inclusion.
Key facts
- Formula
- Ca12(Al4Mg3Si7)O32Cl6
- Family
- Silicates
- Crystal system
- Cubic
- First described
- the Allende CV3 chondrite, 2014
Adrianite was approved as a new mineral in 2014 from a calcium-aluminium-rich inclusion in Allende. It is named after Adrian Brearley, after whom brearleyite is also named. It is known only from meteorites.
What it is
Adrianite is a calcium silicate rich in chlorine, related in structure to brearleyite and the mayenite family. It is not a primary mineral of the inclusion: it grew later, when chlorine-bearing fluid reacted with the original high-temperature minerals.
Where it is found
It occurs as fine grains with other alteration minerals such as sodalite and grossular in a calcium-aluminium-rich inclusion in Allende. Its presence points to fluids moving through the CV parent asteroid.
How it is recognised
It is identified by its chlorine-rich composition and by electron backscatter diffraction in a scanning electron microscope.
Did you know?
Adrian Brearley is one of very few scientists with two minerals named after him.
Chlorine is a tracer of salty water inside asteroids.