Tridymite
- n. Pure silica, like quartz, but crystallizing in hexagonal tables. It is found in trachyte and similar rocks.
The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.