Moon 100mm made of Astrophyllite.

The mineral astrophyllite is a potassium-sodium-iron-manganese-titanium-silicate with the chemical formula K2Na(Fe2+,Mn)7Ti2Si8O26(OH)4. It belongs to the inosilicates.The gold-yellow, bronze-yellow, or brown to brown-red astrophyllite has a diamond to pearl luster, a yellow-brown streak color, and perfect cleavage according to the crystal plane [001]. The average density is 3.34 and the hardness is 3 to 3.5. The crystal system is triclinic and the radioactivity of the mineral is barely measurable. The gamma-ray value according to the American Petroleum Institute is 85.21. The name of the mineral astrophyllite is derived from the Greek words astro ("star") and fylon ("leaf").The mineral astrophyllite is primarily found in zirconium-bearing syenites. The type locality is the Langesundfjord, near Brevik, Norway.