Gems Notes and Extracts Augusto Castellani, Mrs. John Brogden 1871

JACINTH. 115various articles, believed to liave been used ornamentallyby the priestesses of Cybele.The gagat was used in medicine and alchemy. Itwas also used in marking fictile vases indelibly inblack :" Fictilia ex eo inscripta non delentur"XLII.JACINTH.THIS stone, of a fine reddish-yellow colour,is distinguishedas either Oriental or Western.The Oriental is much more esteemed, and chiefly forits colour and hardness. It scratches quartz, but isscratched by corundum ;for which reason it cannot bemistaken for it, although some people have confoundedthem.It comes from Pegu, Ceylon, and Arabia.It isverybright and receives a fine polish, although its lightis rather resinous.It crystallizes in oblong tetrahedral prisms, terminatingin two short pyramids ; has double refraction,and its specific gravity is from 3'631 to 3'687.The Western jacinth is, on the contrary, a verycommon yellow quartz, which is found in Brazil andin France.In colour it is more yellowish than the Oriental.analysis it yieldsOn