Usage examples (6)

• It must be remembered, however, that it is only the orthoclase or potash felspars which contain large quantities of potash -- other felspathic rocks, such as oligoclase...
• There are, for instance, several different minerals commonly classified under the name of felspar, which have been distinguished by mineralogists by the names of orthoclase,...
• They are divisible into two great classes, which have received the names of diorite and dolerite, the former a mixture of albite and hornblende, the latter of augite and...
• Dolerite, when composed entirely of augite and labradorite, produces rather inferior soils; but when it contains oligoclase and zeolites, and comes under the head of...