324 SYSTEMATIC DESCRIPTION OF PRECIOUS STONES 



are many other localities in America at which beryl is found, but none of any commercial 

 importance. 



A small amount of beryl occurs also in Australia ; at several places in New South 

 Wales for example. Here, again, the occurrence has no economic significance. 



Precious beryl of a yellow colour, and also the yellowish-green " aquamarine- 

 chrysolite,"' come principally from Brazil, although it is to be found in good quality at 

 some of the localities already mentioned, for example, in Siberia associated with aquamarine. 

 Beryl of a deep, pure yellow, such as is represented in Plate XII., Fig. 4, is known as 

 golden beryl. It occurs at many beryl localities in North America, especially at Albany 

 in Maine ; it has been collected also in the vicinity of New York City, and in Litchfield 

 County, Connecticut. It is always of sparing occurrence in the States, and, though highly 

 prized there, does not in general command high prices, only exceptionally fine stones costing 

 more than a few shillings per carat. 



Certain of the several varieties of precious beryl are liable to be mistaken for 

 other precious stones which they resemble in appearance ; the exceptionally low specific 

 gravity of beryl, however, prevents any serious confusion. Aquamarine resembles in colour 

 " oriental aquamarine," euclase, some tourmalines, and blue topaz ; its resemblance to blue 

 topaz is so close that the latter is often known in the trade as aquamarine. Each of the 

 four stones mentioned above, however, sinks in liquid No. 3 (sp. gr. = 3'0), while beryl floats. 

 In the same way yellow beryl, that is to say, " aquamarine-chrysolite " and golden beryl, may 

 be distinguished from other yellow and greenish-yellow stones of similar appearance, namely, 

 from yellow topaz, " oriental topaz," " oriental chrysolite," chrysolite, and chrysoberyl, all of 

 which sink in liquid No. 3. To distinguish between yellow beryl and yellow quartz (citrine) 

 is less easy, for there is no great difference between the hardness and specific gravity of these 

 two minerals. In liquid No. 4 (sp. gr. = 2"65) citrine remains suspended while beryl slowly 

 sinks ; moreover, a smooth surface of quartz will be untouched by citrine, but will be 

 distinctly, though not deeply, scratched by beryl. The stronger dichroism of beryl may 

 also serve sometimes to distinguish it from citrine. 



A glass resembling aquamarine in colour may be obtained by fusing together 3456 

 parts of strass, 24 parts of glass of antimony, and IJ parts of cobalt oxide. The single 

 refraction, entire absence of dichroism, and low degree of hardness of this imitation, are the 

 characters whereby it is distinguished from genuine aquamarine. 



EUCLASE. 



Euclase is one of the rarest of minerals and is only occasionally cut as a gem, when it 

 commands fancy prices. It resembles beryl, and specially aquamarine, in many ways; 

 its chemical composition, for example, differs from that of beryl only in the presence of 

 a little water and in the proportions of the constituents, its chemical formula being 

 H^O.^BeO.AiPg.SSiOg. 



The mineral crystallises in the mouoclinic system. The crystals are prismatic in habit 

 and the prism faces are deeply striated parallel to their mutual intersections ; they are 

 terminated at the two ends by obliquely placed faces, as shown in Fig. 64. The crystals 



