18 April 2012

Mineralogy Etymology

Posted by Jessica Ball

It seems like everyone enjoyed the post on the etymology of volcanology vocab, and I did mention something about mineralogy, so…here it is! I’ve mostly pulled up minerals that I deal with in volcanology. (This is just a quick collection – hopefully I’ll get around to posting more once I’m done with my latest round of grad school craziness. Oh, committee meetings…) If you didn’t read the last post, all of this etymology is taken from the Oxford English Dictionary, which is a great place to poke around in if you’ve got the time.

Photomicrograph of the Osiris trachyte (an ash-flow tuff from the High Plateaus of Utah), which contains plagioclase and sanidine feldpsars.

Plagioclase. From plagio-, which means ‘oblique’ or ‘slanting’ in ancient Greek, and -clase, from the ancient Greek for ‘to break’ or ‘to fracture’. Plagioclase has two cleavage planes that generally intersect at 90 degree angles, but not always – which probably prompted the ‘oblique’ part of the word.


Sanidine. From the Greek word for ‘board’ (σανιδ-, σανίς). Sanidines usually show up as flat little board-like crystals (you’ll be familiar with this if you’ve ever picked sanidines for Ar-Ar dating).

Quartz. This one’s tricky. The OED offers up several options for the origins of the word: Middle High German (quarz, quech), possibly referring to an association with a term for ‘dwarf’; and the Polish regional kwardy or twardy (‘hard’), or some other West Slavonic language (Lower Sorbian twardy, Upper Sorbian twjerdy, Czech tvrdý, all meaning ‘hard’ or ‘firm’).

Pyroxene. From pyro-, relating to fire, and the ancient Greek ξένος (xeno-), or stranger. The name is attributed to the French scientist R. J. Haüy, who incorrectly considered pyroxene crystals to be accidental inclusions in volcanic rocks. (Oops!)

Amphibole. This one has some neat origins: in Latin, it’s amphibolum, meaning ‘ambiguous’, which was probably taken from the Greek ἀμϕίβολ or amphibolos, meaning ‘thrown or hitting on both sides’ or ‘ambiguous’. This book says it’s another Haüy contribution, and that he named it “in allusion to the great variety of compositions and appearances shown by this mineral group”. (Also, “Ambiguous Amphibole” would make a great name for a rock band.)

Biotite. Named for French scientist Jean-Baptiste Biot, in recognition for his work on the optical qualities of mica (probably as a consequence of his work on the polarization of light. Biot also made the connection between meteorites on the ground and meteor showers, and did some of the first work with electromagnets.)

Mica. In classical Latin, mica is a ‘grain’, ‘crumb’ or ‘particle’. In post-classical Latin mica means ‘little spark’. There’s also an association with micāre, ‘to glitter or shine’, although the OED suggests that the geologic name probably has to do with the classical meaning. Since mica flakes easily and often shows up in small flakes in schists and gneisses, this makes sense to me.