(also potch opal)
Opal which has no play of colour and is of no value.
More example sentences
- One potential use of common or potch opal is for the production of cristobalite for use as a dental and jewellery investment.
- It often serves as an excellent dark backing for black opals which normally have a thin segment of precious opal naturally formed on a potch backing.
- They usually consist of a very thin opal slice sandwiched between a glass or quartz top and a potch, basanite, jade, or black onyx bottom.
late 19th century: of unknown origin.