This week’s photo is another mineralogy themed one. This photo shows beautiful, yet also flattened crystals of the mineral natrolite that has grown in an acicular habit from a central point making them look sort of like little snowflakes. Natrolite is a relatively common hydrated sodium, aluminum silicate mineral (Na2Al2Si3O10 · 2H2O) that often forms within the void spaces of igneous rocks such as amygdular basalt. In this instance it looks like natrolite has formed along a fracture plane due to its flattened appearance suggesting the only room it had to grow was outward as opposed to up, which is why it has made these “snowflake” shapes.
![Crystals of natrolite along a vein in urtite (foidolite) by Dmitry Zhirov](https://blogs.egu.eu/network/geosphere/files/2015/09/natroliate-1024x824.jpg)
Crystals of natrolite along a vein in urtite (foidolite) by Dmitry Zhirov
Lockwood
There’s also some calcite in there, and the square outlines *may* be apophyllite, but I can’t see enough detail to be confident.
Matt Herod
Good eye Lockwood!!