フェルグソナイト, フェルグソン石 (Fergusonite-(Y))

Here you get the pretty big fergusonite crystal with a flat ending not easy to tell of this is naturally grown or the simple fracture plane. The other thin end of the crystal is this normal fracture. Along all prism faces you can see various typical intergrown structures of the crystal and the crystal shows all over the tetragonal crystal habit. Tetragonal habits are a result of temperatures between 545 two 765 Celsius, those heat treatment after the epitaxy took place finally transform fergusonite in tetragonal shape! The total radioactivity of this piece is around 6 Microsievert per hour thereof only 1.5 Microsievert is caused by gamma radiation!