keratophyre การใช้

• Closely allied to trachyte is the rock type called keratophyre, which is the sodium-rich-plagioclase equivalent of trachyte.
• Geologically, the island is largely formed from keratophyre though the northwest coast and islet of West Tump are formed from basalt.
• The term quartz keratophyre has traditionally been used in the Nordic countries to describe a metamorphosed, felsic extrusive rock, corresponding to rhyolite, dacite, or rhyodacite according to IUGS terminology.