356 Mineralogical Journey. 



length four feet. Its color was a clean, bluish green for the upper 

 three feet of its length, passing into a dull green and yellow at the 

 lower extremity. The faces possessed a considerable polish, and 

 were quite free from longitudinal striae. A slight irregularity was ob- 

 served on a near inspection. The prism had suffered from those ac- 

 cidents which, among strata, are denominated slips; the effect of which 

 had been to give its axis a slightly curvilinear direction. Between 

 the sections which had thus been made across the crystal, thin films 

 or layers of quartz had been interposed. This peculiarity of struc- 

 ture, it deserves to be mentioned, is common to the larger beryls of 

 this locality ; and it may be attributed, possibly, to the circumstances 

 under which the rock forming their bed came into its present situa- 

 tion. Unfortunately, in attempting to free the sides still engaged, by 

 means of a charge of powder in the neighborhood, the concussion 

 produced was so great, as to shiver this noble crystal into fragments, 

 so small as not to allow of its being afterwards set up again. One foot of 

 the base, however, came out nearly entire, which is in my possession. 

 Its weight is fifty nine and a half pounds, thus giving for the entire 

 crystal the weight of tivo hundred and thirty eight pounds."^ I have 

 been the more minute in my account of the above crystal, from 

 the belief that it is the largest hitherto noticed, notwithstanding 

 the testimony of Theophrastus, who mentions having seen one in a 

 temple in Egypt, measuring four cubits in length by three in breadth, 

 and an obelisk of the same gem, forty feet high : both of which are 

 justly conceived, at the present time, to have been masses either of 

 Verd Antique or Porphyry ; since the early Greek writers are known 

 to have called almost every green stone by the name of Emerald. 



Two other Beryls, of large dimensions, were also brought to light 

 by the blast which threw down the one just described ; and there 

 can be no doubt that other crystals of a similar size are distributed 

 through the rock, at pretty uniform distances, as the Feldspar here, 

 seems to be replaced almost entirely by Beryl ; which becomes, so 

 to speak, the equivalent of that mineral, in the composition of the 

 granite. A few feet below the spot, affording the larger crystals. 

 Feldspar begins to preponderate as an ingredient in the rock, the 

 Beryls diminish in size as Vv-ell as regularity, and present for 

 the most part a yellowish tinge, sometimes passing into a deep 



" Allowing 11 p. c. for the propoilioii in which tliti glucine exists in the Beryl, we 

 have 33 pouudd ol" that rare earth in this crystal. 



