_:n5791308111654b8e89986869848d8ea2xb0
<http://schema.org/description>
"Opal Doublets are layered gems, comprising first of the precious Opal, this may be either Milky or Crystal Opal. The second (base) layer, a common Opal backing such as brown ironstone. This process is similar to a venire."
<https://www.aodc.net.au/collections/doublet-opal-rings>