blue john Definition

transparent gem, opaque gem, water sapphire, saussurite, boulangerite, proustite, omphacite, chloropal, horn silver, dyscrasite, grossularite, jamesonite, argyrodite, smaltite, corundom, babingtonite, cerargyrite, stephanite, hauerite, libethenite, skutterudite, chondrodite, cacholong, fluorite, knebelite, berthierite, freieslebenite, pargasite, tyrolite, olivenite, stromeyerite, baddeleyite, lazulite, bournonite, gismondine, eucairite, aurichalcite, mineral, volborthite, helvite, cobaltite, euclase, lanarkite, meionite, strontianite, warwickite, ehlite, miargyrite, polybasite, cyclosilicate, oxalite, hausmannite, martite, gahnite, ripidolite, hyalophane, harmotome, ekebergite, brochantite, phillipsite, calaverite, chalcanthite, gemstone, septarium, rubicelle, okenite, amblygonite, pectolite, ditroite, atacamite, white sapphire, viridite, zinkenite, germanite, anglesite, torbernite, linnaeite, ullmannite, conite, liroconite, petunse, eschynite, cubanite, stannite, annabergite, chemical formula, stinkstone, lepidocrocite, zaffre, rose quartz, sodalite, feldspathoid, hematinon, miascite, bismuthinite, crystallogenesis, caledonite, spinel, garnierite, kerolite,