Fayalite is the iron rich member of the olivine mineral-suite, forsterite being the magnesium rich member at the other end of this suite of iron-magnesium silicates. Most natural olivines are a mixture of the two. This specimen however is nearly pure fayalite, in an rare habitat of rectangular pyramidal crystals, with striations on their surface. Overall length of specimen is 115 mm. Provenance is the vicinity of Mansfeldt, Thuringen, Germany.