Opaque rosin.

CFR · 2024-01-01 · US · Title 7

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.

official document · source cfr-2024 · id 7:§ 160.14