What do you call chemical compounds that are comprised of isolated silica tetrahedron: that is, where the tetrahedrons do not share any corner oxygens with other tetrahedron, but rather are connected by cations in various configurations?  Why, orthosilicates, of course.  Olivine, garnets, zircon, staurolite, and topaz are orthosilicates, to name a few.  So is titanite, one of our favorite Bancroft, Ontario minerals.

When Dr. Robert Lauf arrived at the Rochester Mineralogy Symposium in April he was carting several boxes of his newly minted book entitled “Collector’s Guide to the Silicates: Orthosilicates”.  After his Friday morning talk on the topic, the line to obtain signed copies was predictably long.  I got there early to secure mine, but I do believe Robert was prepared and everyone who desired a signed copy at the symposium was rewarded. Continue reading BOOK REVIEW: Orthosilicates →