2.3" Niobophyllite on a Smoky Quartz Crystal - Malawi

Smoky quartz is a grey-brown to black variety of quartz. This common name is derived from the appearance of smoke within the quartz crystal. Depending on the location and the chemicals present during formation, smoky quartz can appear opaque black, but it is typically translucent to some extent. It is believed that the quartz gains this color from a combination of natural irradiation and aluminum impurities.

Astrophyllite is a rare hydrous potassium iron titanium silicate mineral with the chemical formula (K,Na)3(Fe++,Mn)7Ti2Si8O24(O,OH)7. It commonly forms as radiating, bladed aggregates of soft and brittle crystals, colored golden-yellow to brown. Due to the fragile nature of astrophyllite crystals, they're usually left in situ (within surrounding matrix) for presentation. However, this hasn't stopped jewelers from incorporating polished astrophyllite specimens into jewelry.