Fayalite, Tridymite
Tapuaeharuru Bay, Lake Taupo, Taupo District, Waikato Region, New Zealand
At right is a euhedral fayalite on tridymite and at left is a view of a fractured fayalite in the same vug. The left hand crystal shows that they are, in fact, just a hollow crust with residual iron oxide fragments inside. This is usually due to a later hot gas flow through the rhyolite that is incompatible with the earlier formed fayalites. (Note ...
© Rod Martin