(a.) Of, pertaining to, or like, opal in appearance; having changeable colors like those of the opal.

CM-glass CR-glass achromatic lens adobe aerological instrument agate glass alabaster aneroid barometer aneroidograph astigmatic lens barograph barometer barometrograph beaker bifocals bijouterie billiard table binoculars biscuit bisque blown glass board bottle glass bowl bowling alley bowling green brick bubble bullet-resisting glass burning glass camera camphor glass carnival glass cement ceramic ware ceramics cheval glass china clapboard clear as glass coated lens concave lens concave mirror concavo-convex lens condenser convex lens convex mirror coralene costume jewelry crock crockery crown glass crystal cut glass diaphane display case distorting mirror eggshell enamelware eyeglass eyeglasses eyepiece face fiber glass field glass firebrick flat frosted glass glass house glasses glasslike glassware glassy glaze goblet goggles ground glass hand lens hand mirror house of cards hurricane-hunter aircraft hyalescent hyaline hygrometer ice image ivory jewelry jug junk jewelry laminated glass lath lens level light looking glass lorgnette lorgnon magnifier magnifying glass mahogany marble matchwood meniscus mercury microscope mirror object glass objective objective prism ocular old paper opaline opera glasses pane paper parchment paste piecrust pier glass plane plank plate glass porcelain pot pottery prism radiosonde reader reading glass rear-view mirror recording barometer reflector refractory revet rhinestone safety glass satin scatter pins scope seeing glass shake shaving mirror sheathe shingle shopwindow showcase silk slate slide smooth specs spectacles speculum spy glass spyglass stained glass stemware stone telephoto lens telescope tennis court terrestrial telescope thatch thermal detector thermometer thermostat tile tiling toric lens transparent substance trifocals tumbler urn vacuometer varifocal lens vase velvet veneer vitreous vitrics vitriform vitrine wall in wall up wallpaper watch crystal watch glass weather balloon weather instrument weather satellite weather vane weatherboard weatherglass window window glass window mirror windowlight windowpane zoom binoculars zoom lens