Feldspars, Meet the Feldspars

Feldspar is the most common mineral in the Earth's crust, yet more than any other it's the mineral that separates the amateurs from the pros. To know feldspar intimately takes a petrographic laboratory beyond the means of most rockhounds, let alone the ordinary stone-curious citizen. But I can take you partway there in this article. If you learn what's in there, a lot of things, like igneous petrography, will become much less mysterious.