W. H. VON STREERUWITZ—PRECIOUS METALS OF TEXAS. 
19 
ON THE PRECIOUS AND OTHER VALUABLE METALS 
OF TEXAS. 
By W. H. V. STREERUWITZ. 
Read February 6th, 1892. 
By the term precious metals we generally understand only gold, sil¬ 
ver and platinum, although some of the rarer metals command a con¬ 
siderably higher price. More expressive is the German word cdelmet- 
alle (noble metals). This refers not only to the commercial value 
alone; it also indicates certain qualities, which, abstracting from their 
scarcity, commercial value or the amount of labor and skill required 
for their reduction, give to them a prominent position among the met¬ 
allic elements. So, for instance, to qualify a metal to be an edelmetall it 
requires, before everything, a limited affinity for oxygen, the power to 
resist certain solvents, and perhaps the property to be reduced to the 
metallic state without reagent fluxes. 
Gold, next to iron, has the widest distribution ; it is found in Qua¬ 
ternary deposits and in Archasan schists. It may be found in plutonic 
and volcanic eruptive rocks; in sedimentary formations, as placer gold, 
in nuggets, grains, scales, flour gold, sometimes in crystals; in older 
not sedimentary rock, from which all placer gold derives its origin, in 
veins and veinlets, alone by itself in metallic state, or alloyed with 
other metals or in ores, particularly sulphides, and in this case prob¬ 
ably dissolved rather than disseminated in the ores. The great affin¬ 
ity between sulphur and most of the other metals is wanting in gold, 
but it combines readily with tellurium, and the tellurides may be re¬ 
garded, from a metallurgical standpoint, the equivalent to the sulphides 
of other metals. 
Platinum, up to this time, was found under similar conditions as 
gold, only in the metallic state, alloyed with other metals or pure, to¬ 
gether with the other metals of the platinum group in the placers or 
in older rocks. 
Though the platinum is scarcer, less fusible, resists acids better than 
gold, and is therefore practically more useful, and though its price at 
present is higher than that of gold, it must be regarded less precious 
than gold. Its price fluctuates with the momentary demand, and any 
new “strike” may throw down the price to about half its present 
quotation, which never was and probably never will be the case with 
gold, the market value of which is only slightly altered by specula¬ 
tion. 
Silver exists in nature in the metallic state pure or alloyed to 
