Opaque rosin
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
The term “opaque rosin” shall apply to the article resulting when rosin undergoes internal modification indicated by a turbid, clouded, or opaque appearance, that is, loss of transparency, brought about by the occlusion of moisture or the formation of an excessive quantity of resin acid crystals in the rosin.
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