黄玉(Topaz)x
更新时间:2022-09-29 23:45:50 阅读： 评论：0
黄玉(Topaz)
topazisahard,transparentmineral.itisacompoundofaluminum,silica,andfluorine.gemtopazisvaluable.jewelerscallthisvarietyofthestoneprecioustopaz.thebest-knownprecioustopazgemsrangeincolorfromrichyellowtolightbrownorpinkishred.topazisoneofthehardestgemminerals.inthemineraltableofhardness,ithasaratingof8,whichmeansthataknifecannotcutit,andthattopazwillscratchquartz.
thegoldenvarietyofprecioustopazisquiteuncommon.mostoftheworld'stopaziswhiteorblue.thewhiteandbluecrystalsoftopazarelarge,oftenweighingthousandsofcarats.forthisreason,thevalueoftopazdoesnotdependsomuchonitssizeasitdoeswithdiamondsandmanyotherpreciousstones,wherethevalueincreasaboutfourtimeswitheachdoublingofweight.thevalueofatopazislargelydeterminedbyitsquality.butcolorisalsoimportant:bluetopaz,forinstance,isoftenirradiatedtodeepenandimproveitscolor.
bluetopazisoftensoldasaquamarineandavarietyofbrownquartziswidelysoldastopaz.thequartzismuchlessbrilliantandmoreplentifulthantruetopaz.mostofitisvarietyofamethyst:thatheathasturnedbrown.
