STONES 



STONYHURST 



749 



topaz, chalcedony, jasper, onyx, sardonyx, &c. 

 Among other beautiful and valuable stones much 

 appreciated for ornamental purposes, but scarcely 

 to be classed as precious stones, there may be 

 included lapis lazuli, crocidolite, labradorite, moon- 

 stone, avanturine, and malachite. To the list of 

 precious stones there should be added two sub- 

 stances of animal origin pearls and red coral and 

 perhaps also amber, a comparatively rare and 

 valuable fossil resin. The various substances here 

 enumerated are dealt with, for the most part, under 

 their own proper names. 



For the development of the sparkle, lustre, and 

 glow of colour of most precious stones it is essential 

 that they should undergo the process of cutting 

 and polishing. When lustre and sparkle are the 

 principal qualities to be revealed, as in the case of 

 the diamond, the surface is most favourably cut 

 into numerous plane facets as either brilliant or 

 rose cut stones (see DIAMOND, figs. 1 and 3). 

 When colour is the more important quality of the 

 stone it may, if plane surfaces are wanted, be 

 step or table cut (a in fig.). Such stones also, and 

 translucent and opaque stones, may be cut en 

 cabochon ie. with curved or rounded surfaces. 



The varieties of cabochon cutting are single ca- 

 bochon i In, or high plano-convex double cabochon 

 (c), and double convex and hollow cabochon (d), 

 the latter being much used for large garnets, which 

 HO cut are called carbuncles. 



One of the most important qualities of a precious 

 stone is its hardness, as upon that property depends 

 its power of resisting wear and of keeping the 

 brilliance of its polished surface. It is a property 

 of great constancy, moreover, and in many cases 

 affords a ready means of determining the nature of a 

 stone nnder examination. Of all known substances 

 diamond is the hardest, and representing it, accord- 

 ing to Mohs's scale, by 10, the following is the rela- 

 tive hardness of several of the more important of 

 the precious stones : Diamond, lot) ; sapphire, 

 9O ; ruby, 8'8; chrysoberyl, 8'5; spinel, 8'0; 

 topaz, 8O ; aquamarine, 8 - ; emerald, 7'8 ; zircon, 

 7 "8; tourmaline, 7'5; amethyst, 7'0; moonstone, 

 6 - 3 ; turquoise, 6^0 ; opal, 6O. 



Artificial Preciout Stones. Numerous attempts 

 have been made by eminent investigators to pro- 

 duce artificial precious stones by means of intense 

 heat and pressure and by electrical action ; but 

 hitherto these efforts have failed of practical 

 success. In an important memoir published by 

 Sainte Claire Deville and Caron in 1858 ( Comptes 

 Rendua, vol. xlvi.) they describe various processes 

 by which they obtained small crystals of corundum, 

 ruby, sapphire, &c. By the action of the vapours 

 of fluoride of aluminium and boracic acid on one 

 another, they obtained crystals which, in hardness 

 and in optical properties, resembled natural corun- 

 dum. When a little fluoride of chromium was 

 added a similar process yielded violet-red rubies ; 

 with rather more nuorideof chromium blue sapphires 

 were yielded ; and with still more green corundum 

 was obtained. A mixture of equal equivalents of the 

 fluorides of aluminium and glucinum, when similarly 

 acted on by boracic acid, yielded minute crystals of 

 chrysoberyl. The action of fluoride of silicon on 

 zirconia yields small crystals of zircon, and by the 

 action of silica on a mixture of the fluorides of 

 aluminium and glucinum hexagonal plates of 



extreme hardness were obtained, which in some 

 respects resembled emerald. 



In subsequent researches Becquerel (Comptes 

 Itendus, vol. Iviii.), by the use of electric currents 

 of high tension, succeeded in obtaining opals, &c. 

 from solutions of silicates. Among the most suc- 

 cessful of experimenters in this direction was the 

 late Ch. Fell of Paris, who successfully crystallised 

 alumina, and by the introduction of colouring 

 matter produced sapphires and rubies identical in 

 hardness and composition, but not in brilliance, 

 with the natural stones. M. Feil also succeeded 

 in preparing true crystals of spinel, and a blue 

 lime spinel of great hardness, but which were 

 glassy rather than crystalline in structure. 



Imitations of precious stones consist of a soft, 

 heavy flint-glass called Strass (q.v.) or paste, 

 appropriately coloured, and they may readily be 

 distinguished, among other peculiarities, by their 

 great softness. Fraudulent combinations are made 

 by cementing thin plates of precious materials 

 over, and sometimes also under, a body of valueless 

 glass, and thus the exposed surface or surfaces 

 when tested are real stones, and the veneered mass 

 passes as a genuine large and consequently valu- 

 able possession. 



See works by H. Emannel (1865), W. Jones (1879), A. 

 Delmar (1880), Professor A. H. Church (1883), E. W. 

 Streeter (5th ed. 1892), M. D. Rothschild (New York. 

 1889), and G. F. Kunz (New York, 1890). 



Stone-worship. See FETICHISM, IDOLATRY. 



Stoningtqn, a town and port of Connecticut, 

 on the Atlantic, 14 miles by rail E. of New London, 

 and at the junction of one of the railway and 

 steamer routes between New York and Boston. 

 It has a capacious harbour, a foundry, and tin- 

 factories. Pop. (1890)7184. 



Stoiiyliurst. a great Roman Catholic college 

 in north-east Lancashire, 4 miles SW. of Clitheroe, 

 traces its origin to the seminary at St Omer 

 (q.v.) in France, which was founded in 1592 by 

 Father Parsons (q.v.). The seminary ere long had 

 200 students, but after many vicissitudes was sup- 

 pressed by the tyranny of the Bourbons in 1762. 

 After a short sojourn at Bruges till 1772, and at 

 Liege till 1794 (when the French revolutionary 

 armies were closing round it), the eighteen Jesuit 

 fathers were offered a resting-place at Stonylmrst 

 by Mr Weld of Lnlworth, an old alumnus, to whose 

 family the old home of the Shireburnes had in 1754 

 passed by marriage. The fine house, begun about 

 1594, was beginning to fall into ruin, and even when 

 restored provided but scant accommodation for the 

 200 students who soon flocked to it. Extensions 

 were made in 1810-78, the chapel being built in 

 1835, and other additions have been lately completed. 

 The numbers have gone on increasing with some 

 fluctuations, and are now about 300. The teaching 

 staff numbers over thirty masters ; and there is a 

 preparatory school at Hodder, a mile distant. The 

 department for higher education prepares young 

 men for the London University degree and com- 

 petitive examinations, and puts them through a 

 course of philosophy. In 1840 Stonylmrst was 

 affiliated to the University of London, and it has a 

 long list of successes in the various examinations, 

 especially classics. Between 1840 and 1890 about 

 400 passed the matriculation examination, of whom 

 ninety took honours. The B.A. degree was taken 

 by 120, half of these securing places on the classical 

 honours list, and ten took M.A. in classics and 

 mathematics. The course is mainly classical, but 

 mathematics receives a large share of attention; 

 and French, science, and other branches are 

 essential parts of the course. Games are much 

 encouraged, and special forms of football and hand- 

 ball seem to have been brought from St Omer. 



