Fluorapatite

Fluorapatite in igneous and metamorphic rocks is an important "Capsule" tells history of temperature (thermobarometer), volatile enrichment of melt evolution, and REE pattern which is important for investigating the formation of REE deposits and REE mobility (fluoride complexes during metamorphism).

Here's a classic material but you may not see often. Gemmy, light blue to greenish-blue, columnar, slender gem quality apatite crystals are found mostly as detrial in Mogok Valley, but it's well-preserved from alluvial erosion. This piece was purchased in 2017. I am not sure about the formation of fluorapatite in this specific location due to the complex metamorphic-plutonic geology. I have seen a few matrix (marble) pieces suggest metasometism maybe involved, and an interface-coupled dissolution–precipitation mechanism.

3.5cm long, Oak-saung-taung, Mogok Valley, Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar

Jingnan (Tom) Zhang Coll, Jeff Scovil photo