long since demolished glass works. Lat- 

 terly, however, a Viennese geologist, has 

 advanced the opinion that the fragments 

 are of extra-terrestrial origin and rep- 

 resent a peculiar kind of meteorite. Proof 

 of such an origin of moldavite would 

 lend an added interest to it and prob- 

 ably increase its use for jewelry, the 

 present employment of it being rather 

 limited. The pieces as found are water- 

 worn pebbles of various shapes, usually 

 with deeply indented or pitted surfaces. 

 In size they are never larger than one's 

 fist, and usually much smaller. They are 

 found in the beds of brooks and in the 

 soil. Regions near Budweis and Tre- 

 bitsch are especially prolific in the peb- 

 bles. Moldavite has a hardness not quite 

 equal to that of feldspar, being a little 

 less than 6. It is thus somewhat harder 

 than ordinary glass. Its specific grav- 

 ity ranges from 2.32 to 2.36. Unlike 

 ordinary glass and obsidian, it is almost 

 infusible before the blowpipe and 

 when fused remains perfectly clear on 

 cooling. It differs considerably in chem- 

 ical composition from ordinary glass, hav- 

 ing, as it does a higher percentage of 

 silica and alumina, and a smaller percent- 

 age of alkalies. The percentages of 

 silica range between 88 per cent and 78 

 per cent, those of alumina between 5 per 

 cent and 13 per cent, and those of potash 

 and soda between 1 per cent and 2.5 per 

 cent. In ordinary glass the percentage 

 of silica is not much above 50 per cent; 

 there is almost no alumina, while lime 

 and magnesia amount to about 20 per 

 cent and potash and soda to 20-25 P er 

 cent. 



Glassy pebbles similar to moldavite are 

 found also on the island of Billiton near 

 Java. These are known as Billitonite. 

 They are also found in Borneo and several 

 parts of Australia. In these places thev 

 are believed to be of volcanic origin if 

 not meteoric. 



Of these different occurrences only the 

 Bohemian is so far used to any extent 

 in jewelry. Owing to the abundance of 

 the material the stones cut from it are 

 not expensive, being valued at no more 

 than quartz or agate. Actual glass can 

 easily be substituted for it with little 

 chance of detection. 



HEMATITE. 



Hematite is an oxide of iron which 

 takes on a variety of forms and shades, 

 but is used in jewelry only when com- 

 pact and of an iron-black color. In this 

 form it is used especially for intaglios, 

 but also for carving into ornaments of 

 various sorts. Its hardness is 6 and 

 specific gravity 4.9-5.3. Its compo- 

 sition is, iron 70 per cent and oxygen 30 

 per cent. While in a mass it is invariably 

 opaque and often black in color, but in a 

 thin splinter it may be seen to be slightly 

 translucent and red. This red color al- 

 ways characterizes the powder or streak 

 of the mineral, and is one of the surest 

 means of identifying it. As the color 

 resembles that of blood, the Greeks be- 

 lieved the mineral to be concreted blood 

 and the name hematite is from their word 

 for that substance. Under the name 

 of blood-stone it was long believed 

 to be a curative of hemorrhage, 

 and Robert Boyle, the eminent physicist, 

 writing as late as 1672, gravely relates a 

 cure of a case of nasal hemorrhage of 

 long standing through wearing a blood 

 stone about the size of a hen's Qgg about 

 the neck. 



Powdered hematite forms the rouge of 

 commerce used so extensively for polish- 

 ing. 



Hematite was used in the carved form 

 by the ancients as well as the moderns, 

 a number of gems so prepared having 

 been found in the ruins of Babylon. 

 Large polished surfaces of hematite make 

 excellent mirrors and frequent use was 

 made of it for this purpose in earlier 

 times. Hematite is so abundant over 

 the earth's surface that it has little in- 

 trinsic value except as an ore of iron. 

 That used in jewelry comes largely from 

 northern Spain. Hematite of a similar 

 character is obtained in the Island of 

 Elba, Cumberland, England, and the 

 Lake Superior region of our own coun- 

 try. Besides its use for seals it is em- 

 ployed to make imitation black pearls. 

 Certain fibrous occurrences of hematite 

 when cut in rounded forms give the star- 

 like appearance exhibited by star sap- 

 phires. 



Oliver Cummings Farrington. 



84 



