We publish courtesy of Multibriefs
Author: Gerry Manning, Manning International
How to correct long misrepresented “facts” about opal? Even highly respected labs often misstate information regarding opal characteristics and treatments.
Here are some observations from my personal experience:
• Opal is NOT sensitive to solvents, not unless you’re talking about the same acids that are used to etch glass.
• Opal is NOT sensitive to or vulnerable to ultrasound. I’ve used ultrasound with opal for more than 35 years with no adverse effects.
• Gem opal is NOT — as some have claimed — up to 12% WATER. That, if true, would mean that one could literally shake water from the stone! In fact, there are infinitesimal amounts — or, no water — left in any gem opal. Often, water vapor has remained trapped in the silica lattice. This is where an experienced buyer has a distinct an advantage in providing the market with reliably “cured” opal. I am speaking of Australian, Brazilian and Mexican opal, not some of the less stable varieties that are so porous as to soak up water through their open lattice gaps.