Dominic Mok covered jadeite testing, using a variety of samples including types A, B, C and B+C jadeite; chrome-green cat's-eye nephrite; General Electric synthetic jadeite; and various qualities of jadeite from vivid green to light green ('pea'/'bean' green); lavender, 'icy' and 'glassy' varieties; and
omphacite fei cui that appeared deep green in transmitted light and black in reflected light.
The technique was useful for differentiating areas of jadeite and
omphacite within compositionally and texturally zoned samples.
The main structural characteristics of
omphacite jade and its influence on transparence.
Associated minerals in blue jade are: jadeite, titanian
omphacite, sodic amphibole, titanite, rutile, anatase, strontium-apatite and tausonite.
Claire Mitchell FGA DGA, London, for a reconstituted malachite/azurite, two reconstituted turquoises, two sugilite simulants, and rough and cabochon-cut samples of
omphacite jade from Val Pellice-Alpi Cozie, Piemonte-Nord, Italy.
Chuck Trantham recalls that Jack collected nissonite at the type locality in San Benito County, California, with Charles Chesterman, pumpellyite and
omphacite near Cazadero, California, with George Switzer and Al McGuinness, and parahopeite at Broken Hill, Zambia, with Al McGuinness and Luis Leite.
After reanalysis, these two minerals plus the garnets and
omphacite were routinely used as standards in subsequent studies (2).