320 SYSTEMATIC DESCRIPTION OF PRECIOUS STONES 



quality, and of the length and thickness of a man's thumb, are frequently met with, and 

 the discovery of still larger specimens is not unusual. In his work on precious stones, 

 Barbot, the late Parisian jeweller, mentions a rough aquamarine of rare beauty of which 

 the weight was about 10 kilograms (22 pounds), and for which 15,000 francs (i?COO) was 

 asked. Again, a beautiful grass-green beryl, weighing 15 pounds, was found, in 1811, in 

 Minas Novas, Brazil, and similar finds are often reported. It is not surprising, then, to find 

 atjuamarine and the precious beryls generally among the lowest priced gems, a carat stone 

 of medium quality being obtainable for a few shillings. Only those stones which are 

 exceptionally beautiful in colour and perfect in every other respect command higher prices, 

 and even these fall far short of the value of a fair emerald. In this connection it may 

 be mentioned that the value of beryl, unlike that of emerald, is proportional to the size of 

 the stone. 



Precious beryl, and especially aquamarine, is a mineral of somewhat wide distribution, 

 occurring in gem-quality at many localities. Like the emerald it is met with, for the most 

 part, in its primary situation in druses in coarse-grained granite and similar rocks. Its 

 occurrence in secondary deposits, such as gem-gravels, is less usual, but not so rare as is the 

 case with emerald. 



Brazil is a country in which fine beryl is abundant. Tne stones are often cut before 

 they are exported, but as the form they are given leaves much to be desired they are usually 

 re-cut when they reach Europe. The mineral is found in great abundance, associated with 

 chrysobery], white and blue topaz, &c., as pebbles in the sands of the Minas Novas disti'ict 

 in the north-east corner of the State of Minas Geraes ; also, though sparingly, associated 

 with diamond in the diamond-sands of the same State. These localities, which have been 

 already mentioned under chrysoberyl, will be described in greater detail when Brazilian 

 topaz is under consideration. Among the pebbles of aquamarine are sometimes some of 

 considerable size ; one weighing 15 pounds, which was found in the year 1811 near the 

 source of the Rio S. Matheus, in Minas Novas, has been already mentioned. Another fine 

 pebble weighing 4 pounds was found soon after at the same place ; but, as a rule, the 

 pebbles are much smaller, their greatest diameter being no more than from 2 to 5 lines. 

 The character of the rock in which the pebbles were originally formed is not certainly 

 known ; it is probably, however, a coarse-grained granite, since aquamarine is often found 

 in a similar situation, and other precious stones found in Minas Novas are known to have 

 been formed in a rock of this description. 



In the neighbourhood of Rio de Janeiro aquamarine occurs in coarse-grained granite 

 veins penetrating gneiss. At Vallongo in the year 1825 a fine crystal, weighing 4 

 pounds and valued at ^600, was found. Previous to this had been found at the same 

 place a transparent, faultless stone, which measured 7 inches in length and 9 lines in 

 thickness. 



Beryl is abundant also in the Ural Mountains and elsewhere in Siberia. At many 

 places crystals of gem-quality, associated, as in Brazil, with topaz, are to be found, so that 

 the importance of Siberia as a locality for beryl is comparable to that of Brazil. 



In the Urals it is found at various places in the neighbourhood of Ekaterinburg in 

 the Government of Perm, also on the Ilmen Lake near the Ilmen Mountains, as well as in 

 gold-washings on the Sanarka river in the Southern Urals, the two latter localities being in 

 the Government of Orenburff. 



o 



In the Ekaterinburg district it is found principally in the neighbourhood of the villages 

 of Mursinka (Mursinsk) and Shaitanka (Shaitansk), occurring in drusy cavities in coarse- 

 grained granite, which is penetrated by veins of fine-grained granite. 



