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 Jook, as if they had been 
heated just to incipient fusion. Byrd’s Valley ¢ 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 
triangular in outline, with cavities of the same shape impressed in them. $ 
We may now proceed with a few remarks in regard to the occurrence of 
nuggets in the gravel. It seems to be the fact that the gold in the quartz 
* See ante, p. 115. 
+ Mr. Goodyear gives ‘‘ Mad Cafion near Byrd’s Valley” as the precise locality of the crystallized specimens. 
See ante, p. 114. 
+ 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 calcite or dolomite. 
