isinglass

[prettygoodword]

isinglass - n., any of various minerals (hydrous silicates of aluminum or potassium) that crystalize in a form that cleaves into very thin sheets, such as mica; a transparent, almost pure gelatin prepared from the air bladder of the sturgeon and certain other fishes and used as an adhesive and a clarifying agent.


From probably by folk etymology from obsolete Dutch huizenblas, from Middle Dutch huusblase, from huus, sturgeon + blase, bladder. How that meaning was applied to mica is obscure. Especially since it's such a lovely fancy name for mica.

---L.