Wikipedia
Kenyte
Kenyte is a variety of porphyritic phonolite or trachyte with rhomb shaped phenocrysts of anorthoclase with variable olivine and augite in a glassy matrix. It was originally described and named by J. W. Gregory in 1900 for the occurrence on Mount Kenya. Kenyte has also been reported from Mount Kilimanjaro and Mount Erebus in Antarctica.
Kenyte has a glassy texture and may be composed of devitrified glass, which contains large phenocrysts of anorthoclase feldspar.