Brushiitti

Brushiitti is a mineral with the chemical formula CaAl2(PO4)2(OH)2·6H2O. It is a hydrated calcium aluminum phosphate mineral. Brushiitti is a member of the brushite group, which also includes brushite itself and other related minerals. It typically occurs as a secondary mineral in various geological settings, often forming from the alteration of other phosphate minerals.

The mineral was first discovered in the Bruceton Mine, Pennsylvania, USA, and was named in honor of the American mineralogist George Brush. Brushiitti is usually found as small, colorless to white crystals, often exhibiting a prismatic or acicular habit. It can also occur in massive or granular forms.

Brushiitti is relatively soft and has a Mohs hardness of around 4 to 4.5. It is generally opaque to translucent and can be brittle. The mineral is insoluble in water but may react with strong acids. Due to its often small crystal size and lack of striking physical properties, brushiitti is not commonly sought after by mineral collectors. However, it is of interest to geologists and mineralogists for understanding the processes of mineral formation and alteration. Its occurrence can provide clues about the chemical conditions present during its formation.