is an astrophyllite with high content of magnesium: a hydrous potassium iron titanium silicate mineral with formula K2Na[Na(Fe++,Fe+++,Mn)Mg2]Ti2Si8O26(OH)4F .
Is structure is delicate and fragile,in fact Heavy, soft and fragile, astrophyllite typically forms as bladed, radiating stellate aggregates. It is this crystal habit that gives astrophyllite its name, from the Greek words astron meaning "star" and phyllon meaning "leaf" ( from Wikipedia).
Rarely seen in facet gems, easier in cabochon,or as incrustation on quartz.
From Khibini, Kola Peninsula, Russia.
Size: 10.8x10.8x4.8 mm.
Weight: 3.46 ct.