harmotome
noun
har·mo·tome
ˈhärməˌtōm
: a mineral (Ba,K)(Al,Si)2Si6O16.6H2O consisting of a hydrous silicate of aluminum, barium, and potassium
Word History
Etymology
French, from Greek harmos joint + tomē section, from temnein to cut; from its occurrence in crystalline form with an octahedron dividing parallel to the plane that passes through the terminal edges