DIAMOND: VALUE 255 



5. VALUE OF DIAMONDS. 



The valuation of a diamond, involving as it does a nice appreciation of the defects and of 

 the good points of the stone, and the striking of a just balance between the two, is a matter 

 of no little difficulty, and can only be performed with accuracy and rapidity by an expert. 

 In this section we shall confine ourselves to a consideration of the value of diamonds which 

 are to be used as gems, neglecting those to be applied to technical purposes, the value of 

 which depends on the weight and the current market price. 



Of all the characters which help to determine the value of a diamond there is perhaps 

 none more potent than that of size. Other things being equal, the larger the diamond the 

 greater its value, and, moreover, the ratio of progression in price is greater than that of 

 progression in weight, owing to the comparative rarity of large stones. Since the discovery 

 of the South African deposits, however, this disparity has been less marked, and the value 

 of stones not exceeding a certain size and which are of frequent occurrence, is influenced to 

 a large extent by the exigencies of the trade. Exceptionally large and beautiful stones, the 

 so-called solitaires, paragons, or nonpareils, have, corresponding to the rarity of their 

 occurrence, an exceptional value, which is subject to no rules and is governed solely by the 

 special circumstances of the case. 



The value of a diamond depends very largely upon the form in which it is cut. 

 Although during the process of cutting the weight of a rough stone is reduced by one half 

 or even more, yet its intrinsic value is greater than before, on account of the almost 

 immeasurable improvement in its appearance effected by the faceting. The brilliant is by 

 far the most effective form of cutting, and at the same time is the form which involves the 

 greatest expenditure of skill in the cutting, hence a brilliant-cut diamond commands a higher 

 price than a rose or indeed any other form. Among brilliants themselves different degrees 

 are recognisable, a stone which is correctly proportioned and which bears a large number of 

 facets having a greater value than one less admirable in these respects. A brilliant which 

 possesses no cross facets, the large facets being produced until they meet in the girdle, is 

 described as being " once formed " ; while the terms " twice formed " and " thrice formed " 

 are applied respectively to stones which bear cross facets only below the girdle, and to those 

 which possess these facets both above and below the girdle. The value of a brilliant,, 

 therefore, is the greater the more complex is its form of cutting, and in the same way the 

 value of stones cut in any of the other forms varies with the symmetry and completeness of 

 that form. A perfect brilliant of one carat has at least four times the value of a rough 

 stone of the same weight and quality, and five-fourths the value of a rose of this size and 

 quality. 



The value of a rough stone also is influenced to a certain extent by its form, for, as we 

 have seen, stones whose form in the rough approximates most nearly to that of the cut stone 

 are most favourable for cutting. Thus octahedral and rhombic dodecahedral crystals can be 

 fashioned into brilliants with less labour and loss of material than is the case with irregularly 

 shaped stones, which often need considerable preliminary shaping, if not actual division into 

 portions suitable for cutting. Among such stones must be included flat specimens, like the 

 twinned crystals shown in Fig. 31, g* and h, which cannot be cut ns brilliants and are suitable 

 only for cutting as roses. Another property which greatly facilitates the process of cutting 

 is that of cleavage ; a simple crystal, from which the cleavage octahedron can be readily 

 developed, is therefore far more desirable than a twinned crystal, such as is shown in Fig. 31 i, 

 or an irregular crystal group which, as often as not, can be utilised only as bort. 



The value of a diamond depends most of all, however, on the degree of its transparency. 



