1. potch - Noun
2. potch - Verb
To thrust; to push.
See Poach, to cook.
Source: Webster's dictionaryAn opal doublet consists of a relatively thin layer of precious opal, backed by a layer of dark-colored material, most commonly ironstone, dark or black common opal (potch), onyx, or obsidian. Source: Internet
Contrarily, opalescence is correctly applied to the milky, turbid appearance of common or potch opal. Source: Internet
These include: casting, faceting, carving, jewelry, mosaics (e.g. little slices of opal on potch, obsidian or another black stone and with a clear dome (glass or crystal quartz) on top. Source: Internet