appearing darker red in reflected light. 

 The Hghter red and yellowish shades are 

 less desirable, stones of these shades be- 

 ing known as "female carnelians," while 

 those of the darker shades are known as 

 "male" carnelians. The colors are due 

 to 6xides of iron and can sometimes be 

 changed by heating. Thus the yellowish 

 and brownish carnelians heing colored by 

 iron hydroxide can be changed by heat- 

 ing to red, the water being driven off and 

 iron oxide left. The heating may be 

 done in the sun or by some other slow 

 means. Even olive green stones are 

 changed in India to red by this process. 

 The color may also be introduced artifi- 

 cially by allowing the stones to lie in a 

 mixture of metallic iron and nitric acid, 

 or of iron sulphate for a while. In this 

 way the iron salt needed for the coloring 

 matter can be absorbed by the stone and 

 this is changed afterwards to oxide by 

 heating. The best carnelians come from 

 India, but good stones are also obtained 

 in Siberia, Brazil and Queensland. Car- 

 nelians are cut usually in oval and shield- 

 like shapes and were much employed by 

 the ancients for intaglios. They believed 

 them to have the power of preventing 

 misfortune and they were much worn as 

 charms. 



Sard of typical brown color is much 

 rarer than carnelian and possesses a high 

 value. In other respects it is like car- 

 nelian. The sardius mentioned in the 

 Bible as forming one of the stones of the 

 High Priest's breastplate was undoubt- 

 edly a carnelian. The name was derived 

 from Sardius, a city of Lydia whence 

 fine carnelians are obtained. The name 

 carnelian is according to some authorities 

 derived from the Latin word caro, car- 

 nis, flesh, and refers to the color of the 

 stone, or according to others it is from 

 the Italian word carniola which has the 

 same meaning. 



Chrysoprase and Prase. are terms ap- 

 plied to an apple green to bright green 

 chalcedony or compact, jasper-like form 

 of quartz. Some authorities, however, 

 call the green chalcedony plasma and re- 

 strict the term chrysoprase to the green 

 compact quartz. The terms cannot be 

 accurately distinguished. Most chryso- 

 prase now in use comes from localities 

 in the province of Silesia in Germany, 



where it occurs in thin layers and veins 

 in serpentine. The green color here is 

 due to nickel oxide which' is present in 

 the stone to the amount sometimes of one 

 per cent. The first discovery of the stone 

 is said to have been made by a Prussian 

 officer in 1740. The stone was especially 

 fancied by Frederick the Great so that he 

 had two tables made of it and used it 

 frequently in mosaics. The color fades 

 with light and heat, but it is said can be 

 restored by burying the stone in moist 

 earth for a time. Beautiful chrysoprase 

 comes from India and there are a few lo- 

 calities in our own country where it is 

 found, it being usually associated with 

 nickeliferous deposits. The name chrys- 

 oprase comes from two Greek words 

 meaning golden leek and refers to the 

 color of the stone. 



Plasma, as already stated, is a name 

 applied to green chalcedony, or by some 

 to green jasper. The name comes from 

 the Greek for image and shows that the 

 stone was largely used for seals and 

 other engraved work. Most of that 

 known at the present time comes from 

 India and China. 



Bloodstone is a variety of plasma con- 

 taining spots of red jasper looking like 

 drops of blood. x\nother name for blood- 

 stone by which it was chiefly known by 

 the ancients is heliotrope. This name is 

 derived from two Greek words mean- 

 ing "sun turning" and refers to the 

 belief that the stone when immersed 

 in water changes the image of the sun 

 to blood red. The stone was often used by 

 the ancients for carvings rej)resenting 

 the head of Christ, and one fine 

 specimen of such work may be seen 

 in the Field Columbian Museum. The 

 ancients had a tradition that the stone 

 originated at the crucifixion of Christ 

 from drops of blood drawn by the 

 spear thrust in his side falling on a 

 dark green jasper. The stone takes a 

 beautiful polish. To be of the best qual- 

 ity it should have a rich dark green 

 color and the red spots should be small 

 and uniformly distributed. The supply 

 is obtained almost wholly from India, 

 especially from the Kathiawar Penin- 

 sula west of Cambay, whence agate, 

 carnelian and chalcedony are also ob- 

 tained. Fine examples have also come 



