DIAMOND 



1785 



DIAMOND 



very small diamonds are formed at the center 

 of the lump; this would seem to indicate the 

 process of diamond formation carbon sub- 

 jected to great heat and the tremendous pres- 

 sure of cooling. It has long been known that 

 a beautiful diamond, if heated very hot in 

 a vacuum, or place without air, expands or 

 swells and becomes ordinary black charcoal. 

 If subjected to intense heat while in the air, it 

 disappears as carbonic acid gas. 



Characteristics. Diamonds form in crystals 

 (see CRYSTALLOGRAPHY). Some of the crystals 

 have four sides, shaped like those of a cube; 

 some have eight sides, forming a double pyr- 

 amid ; others have twelve faces, each face being 

 a parallelogram, and there are various other 

 forms. The great brilliance of the cut stone, 

 which is not disclosed in the rough, is due to 

 the power of the diamond to refract, or break 

 up, light, and this power is very much enhanced 

 by the little planes, or facets, of the cut. The 

 stones cannot be dissolved or hurt by acids and 

 can be made to glow in the dark by rubbing, or 

 after having been in the sunlight or in the 

 presence of radium. Some stones, when sub- 

 jected to a current of electricity in a vacuum, 

 glow wonderfully. As diamonds are the hardest 

 material known in the world, they can be cut 

 and polished only by contact with other dia- 

 monds. 



Value. We sometimes confuse the meanings 

 of the two words, valuable and costly. Dia- 

 monds are certainly among the most costly 

 things in the world, partly because they are 

 very rare. There is no reason why the diamond 

 should be a rare stone, except from the fact that 

 those who own the fabulously-rich mines pur- 

 posely limit the output. There are known to 

 be sufficient diamonds in the mines of the 

 world to supply all the people who would like 

 to own such a stone, and they could be sold 

 at retail at $10 per carat at a reasonable profit. 

 However, the mine owners restrict the output 

 every year to meet only the demand that 

 continues at the high prices maintained. Dia- 

 monds are weighed in carats; in the rough at 

 the mines they are priced at sums ranging from 

 $8 to $15 a carat, and when ready for sale they 

 cost $100 to $200 or more per carat, according 

 to quality. That is only an average estimate. 

 Some of the larger stones have been valued 

 at fabulous sums even before cutting. Some 

 cuts are more costly than others, for cutting is 

 very difficult, and the kind of cut depends 

 somewhat upon the quality of the stone. The 

 cuts most used are the brilliant and the rose. 



Diamond Cutting. In olden times, diamonds 

 were cut in a very crude fashion. In the Dutch 

 city of Bruges in 1746 was established a trade 

 guild of lapidaries, or stone cutters, under the 

 master cutter, L. von Berquem. Other guilds 

 were soon established in Antwerp and Amster- 

 dam, and these cities, particularly the latter, 

 have to this day retained preeminence in the 

 art of diamond cutting. The tools used are 

 exceedingly simple, and practically everything 

 depends upon the skill and knowledge of the 

 artisan. 



Uses of the Diamond. Because of its hard- 

 ness, it is superior to any other material for 

 cutting and drilling. Glass fitters use diamond 

 points with which to cut their glass. Diamond 

 dust, saved from the process of cutting, is 

 used for fine polishing. The points of engrav- 

 ing tools for hard surfaces, such as glass and 

 steel, are diamond points. Very small dia- 

 monds are used as bearings in watches, and on 

 the points of gold pens; and larger ones are 

 lenses in microscopes. On the end of stone 

 drills, diamond points are invaluable because 

 they stand great weight and great pressure. 

 Carbonado, a form of diamond not suitable for 

 gems, is more valuable on drills than the dia- 

 mond itself, for it is slightly harder, is not so 

 perfectly crystallized, therefore has less cleav- 

 age and is less likely to break. Diamonds in 

 which are drilled tapering holes are used for 

 wire drawing. A permanent, indestructible dia- 

 mond needle is used in some varieties of talk- 

 ing machines. Besides these most common 

 uses, there are a few other technical mechanical 

 uses of diamonds. 



Diamond Fields, The most ancient gems are 

 known to have come from India, where the 

 industry of gathering these stones was first 

 carried on. The natives of low caste were the 

 workers in this field, and the methods em- 

 ployed were the most primitive. The stones 

 were found in the gravel and the sands of 

 streams and removed as are gold nuggets in 

 placer mining, the fine gravel being washed 

 away in sluices and the nuggets picked out 

 from among the larger stones. Golconda was 

 the market for many of the Indian stones 

 which have become known by that name. At 

 the present time no diamonds are exported 

 from India, and many of the old mines are no 

 longer worked. In Brazil in 1727 valuable dia- 

 mond fields were discovered whose stones ex- 

 celled in quality those of India. 



The story goes that in the year 1867 a trav- 

 eler in South Africa paid a few pennies for a 



