The Glass Mountain is a geologic formation in Lower Cathedral Valley of Capitol Reef National Park consisting of large selenite (gypsum) crystals forming a mound or plug 15 feet high. Gypsum was deposited as sea water evaporated 165 million years ago and then buried under other sediments. The gypsum migrated upwards through fractures in the sediments forming layers and, very rarely, domes like the Glass Mountain. There is only one exposed selenite plug within the park and one other just outside which has been reduced to ground level by collectors.
I’ve been to Lower Cathedral Valley many times, over 200, but mostly been limited to showing tour guests the main features in the valley for a few minutes. Today I decided to explore a valley to the north of the Temples.