Anatase with Quartz, Albite and Calcite

Prenteg is famous for the occurrence of the trimorphous minerals Anatase, Brookite and Rutile, three of the five natural forms of titanium dioxide.  Prenteg is the type locality for Brookite.  Alpine cleft mineralisation occurs throughout this region of Wales and this lovely miniature is a fine example.  The top surface of a slightly chloritized granitic matrix is covered with crystals of Quartz, Albite and Calcite and towards one end sit two well-formed Anatase crystals, the larger measuring 3 mm across.  Each Anatase crystal forms a four sided striated pyramid of translucent clove brown.  This choice specimen comes with a Richard W. Barstow Collection white label.