Opal, Sulphur
Lake Rotokawa, Wairakei, Taupo District, Waikato Region, New Zealand
A piece of stromalitic sinter formed of layers of opal-A and opal-C in a silica rich hot pool. The water in the pool has then changed to acidic sulphur bearing water that has led to the deposition of pillow like structures of fine, muddy, sulphur (right hand side) and small branching structures of orthorhombic, muddy, sulphur crystals (left hand ...
© R.J.Martin