GLOSSARY – W-X-Y-Z

GLOSSARY – W-X-Y-Z

by: Charles O’Dale

WADSLEYITE, β-Mg2SiO4 
A high-pressure phase of polymorphous Mg2SiO4. An orthorhombic mineral. It was first found in nature in the Peace River meteorite from Alberta, Canada.

ZIRCON
Zircon, zirconium orthosilicate (ZrSiO4), is found in most igneous rocks and some metamorphic rocks as small crystals or grains. Zircon transforms into reidite when the latter is subjected to very high pressures.
Reidite is a rare mineral,  a dense form (polymorph) of the fairly tough gemstone zircon.  Reidite has been found in crater impacts: the Chesapeake Bay Crater in Virginia, Rock Elm Crater in Wisconsin.
[see – SHOCK METAMORPHISM – reidite]