



■^^HVBV 



.: ■H^H ■ 





358 



RESUME AND THEORETICAL DISCUSSION. 









. 







Crystallized gold is of extremely rare occurrence, and it appears to be 

 limited to a few favored localities. No instance has ever come under the 

 writer's eye of a perfect crystal with smooth sides and sharp edges; irreg- 

 ularity of outline, rounded faces, and imperfect edges are the rule. The 

 octahedron is the predominating form,, with various modifications ; not a 

 specimen in cubic form has ever been seen or heard of by the writer. Iso- 

 lated crystals do occur ; but groups are far more common, and they are 

 almost always imperfectly developed, and aggregated in arborescent and 

 filiform shapes, or implanted on broad leaves or plates. Some of the speci- 

 mens of this kind are of great beauty. Spanish Dry Diggings is a famous 

 locality for crystalline masses of gold. The specimen to which reference was 

 made by Mr. Goodyear in his description of this locality # seems to have 

 been one of the most strikingly beautiful ever discovered. It was very 

 irregular in shape, fifteen inches in length, and about six and a half inches 

 in its greatest, and two in its least width. While appearing, as described 

 by Mr. Goodyear, to be a mass of " imperfect arborescent crystallizations, 

 it exhibited few well-developed planes; but the writer had no opportunity 

 of making a minute examination of this specimen. Others, much smaller, 

 but of great beauty, from the same locality, and taken out at about the same 

 time, are in irregularly branching, leaf-like forms, studded with triangular 

 plates with bevelled edges, these plates are sometimes very sharply defined, 

 but more generally they have a peculiar blunted look, as if they had been 

 heated just to incipient fusion. Byrd's Valley f is another famous locality 

 of crystallized gold. The specimens from that place, so far as the writer 

 has had an opportunity to observe, are much more distinctly crystallized 

 than those from Spanish Dry Diggings. They consist of groups of octahedra, 

 of many of which the skeleton only exists, the crystal looking exactly as if 

 it had been cast in a mould, and then the remainder of the metal allowed to 

 run off as soon as the edges had hardened. Some forms are tabular and 



•>y 



triangular in outline, with cavities of the same shape impressed in them4 



We may now proceed with a few remarks in regard to the occurrence of 

 nuggets in the gravel. It seems to be the feet that the gold in the quartz 



* See ante, p. 115. 



+ Mr. Goodyear gives "Mad Canon near Byrd's Valley" as the precise locality of the crystallized specimens. 

 See ante, p. 114. 



t Professor W. P. Blake, in his Catalogue of California Minerals (in J. Ross Browne's First Report, 1867, 



■ 



p. 204), gives several localities where crystallized gold had been found in the Sierra Nevada. All the crystals 

 mentioned are described as having an octahedral form, sometimes slightly modified. Specimens from the Princeton 

 Mine are spoken of as having "brilliant faces." Two localities are mentioned of gold in caleite or dolomite. 





it ■ 

 ■ 





