QUARTZ (ROCK-CRYSTAL) 477 



Alpes, and the water-clear stones cut here were called " Brian9on diamonds." The working 

 of rock-crystal at this place has long been abandoned ; and, indeed, the Alpine material has 

 now very little industrial significance, being replaced by Brazilian crystals, which are not 

 only purer but also cheaper. 



The weathered debris from the higher Alps, which contains rock-crystal detached from 

 the parent rock, is transported to lower levels by glaciers and streams. The crystals are 

 rolled along the beds of streams and rivers, becoming as they travel further down the 

 valleys more and more water- worn, until at last they take the form of peifectly rounded 

 pebbles, which, on account of surface scratches, appear to be cloudy, but which in reality 

 are perfectly transparent inside. Such pebbles, the biggest of which are the size of a 

 nut, are fouud in the Rhine, having reached this river through the Aar. At many 

 places in Baden they were at one time cut under the name Rhine-quartz (Germ. 

 Rheinkiesel) and constituted a by-product of the gold-washing industry. This Rlieinkiesel 

 was formerly, though incorrectly, considered to be finer and purer than the rock-crystal 

 which had been brought down the Alps by other means. Similar pebbles were found 

 and occasionally utilised in the same way at other places, for example, at Medoc and at 

 Alen^on (" Alen^on diamonds ") in Normandy, at Fleurus in Belgium, and at Cayenne. 



There are many extra-Alpine occurrences of rock-crystal, but only a few will be 

 mentioned here. Magnificently clear, though not very large, crystals occur in the 

 cavities of the world-famous statuary marble of Carrara in Italy. Very fine water-clear 

 crystals, developed on all sides and often showing no distinct point of attachment, occur 

 in the cavities of the dark Carpathian sandstone, or in the clay-slates with which it is 

 interbedded, in the Marmaros Comitat, in north-east Hungary, bordering on Galicia. 

 The crystals range in size from that of a pin's head to that of a nut ; they are collected 

 at the surface of the ground usually after heavy storms of rain. They have a wide 

 distribution iu the district, but Veretzke, in the valley of the Nagyag river, and Bocsko may 

 be mentioned as typical localties. In reference to the region in which they occur these 

 crystals are known as " Marmorosch diamonds." Small rock-crystals are found in crevices in 

 Triassic (Lettenkohle) marl, in the Hessian county of Schaumburg, on the lower Weser. 

 These were known as " Schaumburg diamonds," and were formerly used as gems, only a 

 small proportion, however, being perfectly clear and fit for cutting. 



In England fine, transparent rock-crystal is found in quartz-veins in slate at Tintagel 

 and Delabole, in Cornwall, and elsewhere ; they are known variously as " Cornish diamonds," 

 " Bristol diamonds," &c. 



Although the occurrence of fine rock-crystal in Europe is very abundant, it is far 

 surpassed by that of other parts of the world. A large amount was being obtained from 

 Madag^ascar at the end of the eighteenth century, and a considerable amount still comes 

 from that island. The material found here is specially pure and clear, and often occurs in 

 blocks of some size, the largest measuring as much as 8 metres in circumference. It 

 occurs in special abundance in the form of isolated, partially water-woi-n blocks on the 

 slopes of the Befoure mountains, where it is collected for the market. Large blocks of 

 perfect quality, and weighing from 50 to 100 pounds, are not at all uncommon, and it is 

 the abundance of excellent material in Madagascar which has caused the depreciation in 

 prices. 



Rock-crystal is common in India also. It was, and is still, worked there in various 

 ways, but the objects now carved and worked in this material do not bear comparison with 

 those of by-gone times. The industry is still in operation at Vellum, in the Tanjore district 

 of the Madras Presidency, where brilliants, rosettes, spectacle-lenses, &c., are produced. 



