Teschenite
“The analcime-bearing gabbro”
Teschenite is a dark, medium- to coarse-grained intrusive rock similar to gabbro but containing the zeolite mineral analcime instead of feldspathoids or quartz. It typically forms as sills in sedimentary basins and is relatively rare, making it a rock that most geologists encounter only in textbooks.
plagioclase, augite (titaniferous), analcime, olivine, biotite, magnetite, apatite
Těšín/Cieszyn (Czech Republic/Poland — type locality), Edinburgh (Scotland), Midland Valley (Scotland), Hokkaido (Japan)
5-6
Edinburgh's famous Arthur's Seat and many of its surrounding sills contain teschenite — meaning Scotland's capital city is literally built around and on top of this uncommon rock type.
Test Your Knowledge
What unusual mineral replaces feldspathoids or quartz in teschenite, distinguishing it from ordinary gabbro?
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