This is a 5" wide polished prehnite section, collected from Wave Hill, Australia. The back portion is still rough, however the "front" has been cut and polished, revealing the beautiful prehnite formation structure. This specimen comes with an acrylic display stand.
Prehnite is a calcium aluminum silicate with the chemical composition Ca2Al(AlSi3O10)(OH)2. It generally occurs as volcanic cavity infillings, and typically is a shade between yellow and green, however colorless and blue specimens are not unheard of.