WotD: diatomaceous earth

1. die Kieselgur, die Diatomeenerde
2. de diatomeeënaarde, het celiet
3. la diatomita, la tierra de diatomeas
4. la diatomita
5. le kieseguhr, la terre diatomée
6. an chré dhiatómúil
7. y diatomit
8. ziemia okrzemkowa
9. 규조토 (珪藻土)
10. 矽藻土 xīzǎotǔ
11. 珪藻土 (けいそうど)

Notes: It never would've occurred to me that this would be a term worth looking up until a book came across my desk with the title Kieselgur. Kiesel I recognised as meaning "gravel", but the second element was puzzling. (As well it might be, being a dialectal term related to gären which has been adopted into geological jargon to designate a type of gypseous deposit.) I've acquired diatomaceous earth once in my life to kill some ants; it never occurred to me that it was the fossilised remains of tiny sea creatures, let alone that it was first discovered and mined beneath the Lüneburg Heath of Germany.

Diatoms are a type of phytoplankton with a silica cell wall, and though the name may seem to suggest they are only two atoms across, in fact it refers to their bilateral symmetry (lit. "cut in half"). The Polish and Chinese names reference their chemical composition, with the former being a diminutive of krzem "silicon" and the latter glossing as "silicon algae". The Korean and Chinese are more curious, as 珪 is an obscure character for a jade tablet which was used as a symbol of authority in feudal times. Here it's most like a substitution for the homophone 硅 "silicon", but I like to think of it as fancy variant of 圭, which counts among its other archaic meanings "a unit of dry measure equal to roughly 10.35 mL"