Sibyl Dunlop
Dunlop's work is characterised by the use of semi-precious and precious gems , such as chalcedony , chrysoprase , moonstone , amethyst , agate , quartz and opals , often cabochon rather than facet-cut gemstones , set in silver in symmetrical patterns , often inspired by nature . 
<triplet> chrysoprase <subj> chalcedony <obj> subclass of <triplet> amethyst <subj> quartz <obj> subclass of <triplet> agate <subj> quartz <obj> subclass of