Minerals / Prehnite, Loanhead quarry.

   Prehnite is an inosilicate with the formula Ca2Al(AlSi₃O₁₀)(OH)₂  It is a hydrothermal mineral, filling cavities in basaltic volcanic rocks, and also lining fractures in various intrusive and metamorphic rocks. The specimen is from Loanhead quarry, Nr. Beith in Scotland, and is a botryoidal aggregate with no crystals observed. part of the surface is peppered with small calcite "rosettes" with a slightly orange colouration. Prehnite of suitable quality is much used in jewellery.

A To Z Of Minerals...

Back To Home...