Was: Turquoise doublet
Opals and opal doublets are valued as separate entities. An adjustment to value based on whether there is backing or not is a valuation relic left over from real estate methodologies and questionable retail practices. The differences in backed and nonbacked opals are so varying that a formula does not due it justice, nor is it remotely accurate.
This is valuable I’d really like to hear more about
this from appraisers and cutters.