I mostly write about minerals that are abundant and occur in many places. The mineral I am writing about today is nothing like that. Charoite was first properly described in 1978 and it is so far known from only one locality. The Murun Massif in eastern Siberia is a syenitic magma intrusion. There are metamorphic aureoles commonly surrounding such intrusions which may contain unusual minerals.
In our particular case the rocks surrounding the intrusion are limestones. So it is a mineral that got lots of calcium from limestone, and Potassium + silicon from syenitic magma. We can say that charoite is yet another calc-silicate mineral and the rock itself is another version of skarn.
This mineral is a hydrous chain silicate, but it does not belong to the amphibole group. The mineral that is commonly associated with it is another rare chain silicate canasite.
Charoite (purple) with canasite (light-colored). Murun Massif, Sakha Republic, Russia. Width of sample 8 cm. TUG 1608-4301.