Thank you Joe for the very kind words, I hold you in the same regards. Paul put this situation very clearly, that all the info we have publicly, says the Dutchman ore is not epithermal, nor any mention of any tellurides. We cannot take the word of someone who says he or she has seen proof to the contrary.
I think Will has an excellent idea to simply ask Dr Glover if tellurides were confirmed as present in the jewelry and - or camp ores. I do not know Dr Glover personally but have had a couple of contacts with him, and hope to meet him some day.
I still can't agree that black minerals are tellurides. Here is an article written for geologists on how to ID the telluride minerals;
http://www.minsocam.org/msa/collectors_ ... urides.htm
Here are the colors listed for the various tellurides:
As far as I can determine, none of the tellurides would be found in nature as a black colored mineral. I will agree that we cannot make any absolute conclusions based on just looking at photographs, but I thought that the typical silvery-white or brassy yellow of most gold tellurides would be readily noticeable to the naked eye.Altaite-PbTe
Color, galena white; hardness B; nearly sectile. Isotropic, but some specimens exhibit weak anomalous anisotropism Cubical cleavage is prominent inmost specimens, as exhibited by two sets of cleavage cracks at right angles, but does not show triangular pits like galena.
Calaverite-(Au, Ag) Te2
Color, light yellow to pinkish-white; hardness C. Strongly anisotropic, polarization colors are light gray, brown, dark gray. Some specimens show multiple twinning.
Coloradoite-HgTe
Color, light pinkish gray; hardness C, appears sectile in small grains. Isotropic.
Hessite-Ag2Te
Color; light gray; hardness A; nearly sectile. Most specimens are strongly anisotropic and show multiple twinning: polarization colors white, steel-blue, bornite-pink. The writer has never seen a specimen of isotropic hessite and the isometric character is open to question.
Krennerite-(Au, Ag)Te2
Color, creamy white; hardness C. Strongly anisotropic, polarization colors light gray, yellow, brown. Some grains show multiple twinning.
Petzite-(Ag, Au)2Te
Color, galena white; hardness A; nearly sectile. Isotropic.
Sylvanite-(Au, Ag)Te2
Color, silvery-white to creamy-white, lighter than calaverite; hardness C. Strongly anisotropic, with multiple twinning; polarization colors light gray, brownish-gray, dark gray.
Tellurium-Te
Color, silvery-white; somewhat lighter than krennerite and calaverite, distinctly lighter than hessite; hardness B. Strongly anisotropic, polarization colors light to dark gray.
It does not make a large difference to me how Dutchman ore is classified, but your comments insisting that it is epithermal while refusing to provide any kind of documentation to support that contention, which is contrary to the published opinions of the experts consulted by Dr Glover leaves us looking for answers. I am not calling anyone a liar if they should say they saw test results which prove epithermal & tellurides, just that I would like to see those test results too. It is a bit unreasonable to expect others will ignore the published expert opinion in favor of the word of someone we have never met.
About the tellurides; I went back to re-check some of the sources I have on hand, to see if someone had identified them in ores of one of the historic mines of the area; and perhaps I simply missed it or forgot about it. I can't find any mention of tellurides being found. Here is one example, from a study done by government geologists
This is taken from GEOLOGIC MAP OF THE GOLDFIELD QUADRANGLE AND THE NORTHERNMINERALIZATION
Superstition Mountains: Little mineralization is visible in the welded tuff. East of the First Water Trailhead, hematite is locally abundant on fault and fracture surfaces. Locally, minor light grey chalcedony also fills some fractures. No other mineralization was seen.
To the south of Hieroglyphic Canyon, many prospects have been dug into Pinal Schist. Epidoterich foliated amphibolite lenses locally contain traces of chrysocola, hematite, and white quartz, especially near the contact with the Pinal Schist. Chrysocola stains are locally visible at the contact between Pinal Schist and nonfoliated diorite (map unit YXd).
In the south-central part of section 35, a hill of white quartz, locally stained with hematite, crops out within granite. There are several dirt roads leading to the hill, which has been heavily quarried, but no evidence of hydrothermal minerals other than quartz was seen. Below black Mesa a thin rhyodacite flow has been mostly altered to light grey porcelanite such that, in most areas, all that is visible are 1-4 mm clear, subrounded quartz phenocrysts in a light grey aphanitic matrix. A few dikes in the area have also been similarly altered.
Goldfield: [Because many of the mines around Goldfield have been disturbed, partially buried or completely covered, it was not possible to directly study most of the workings. Therefore, much of the following was taken (and modified) from an unpublished report by lD. Wilburn.] The Superstition Mining District (later termed the Goldfield Mining District by Keith and others, 1983) was established in 1893 and
includes the area in and around Goldfield (see figure . Though not a large district locally, the ore was incredibly rich .. During its heyday from 1893 to 1898, the Mammoth, Bull Dog, and Black Queen mines produced $1 million in gold and silver from rich electrum deposits. A dozen smaller mines also have produced gold and silver. Sporadic mining in the district, as late as 1986, produced a total of about 60,000
ounces of gold and 20,000 ounces of silver. Throughout the Goldfield area, faults and fractures are locally filled with coarse-grained calcite and crystal-rich dacite dikes having mineral compositions similar to the dacite lavas (map unit Tdc). In
fact, all dikes observed were the same composition. Locally, broad areas of rock have been hydrothermally altered. Two miles south of Goldfield hills of dacite are altered to light hues of pink, green and grey. The mafic minerals have been weakly altered to hematite and the feldspars appear to have been altered to clay minerals. Chloritic alteration and dark hematite staining (possibly from the alteration of disseminated
sulfides) was also seen. Many outcrops display small areas of iridescent limonite, with metallic colors resembling bornite. The colorful outcrops have attracted prospectors, evident by shallow pits and trenches in the area. Intense hydrothermal alteration occurs in the white-colored pits just south of Mountain View road, where most of the area is light colored clay and possibly gypsum(?). Hydrothermal solutions have preferentially altered the dacite. Locally. however, the lowermost 3 meters or so of basalt is also altered to light shades of pink and tan. Chrysocola stains fractures (N15°W, 55°) in basalt on hills almost 3 miles north of Goldfield. In this area manganese films are common on fractures in dacite.
Mammoth Mine. The district's largest mine, the Mammoth, was dug into arkosic conglomerate along one or more north-trending normal faults. Outcrops are very limited, but the fault(s) separate conglomerate and basalt in the hanging wall block from granite in the footwall block. Immediately to the south of the mine an exposure of dacite crops out in a large trench. The dacite is bounded on both the east and west by high-angle contacts but the dacite is white and hydrothermally altered to clays, and the exposures in the trench are crumbly and indistinct. It is possible that the dacite is not a down-dropped block, as shown on the map, but is actually an intrusion. The electrum-rich Mormon Stope in the mine occurs within a high-angle shear zone (here called the Mammoth Fault) 30 feet wide, and dips 83°W. Between 65 and 200 feet below the surface the Mormon Stope preduced ever 40,000 ounces of gold. Gold
occurred abundantly as wire, dust, and flakes in white te glassy quartz stained strongly by pyrolusite, hematite, and limenite. A smaller ore bedy occurred 500 feet south on the fault. Rich ore extended to 400 feet in narrow veins. Below 1,022 feet, ore values diminished.
Black Queen Mine. The Black Queen Mine lies about 3,000 feet north of the Mammoth Mine in a zone of complex faulting. In the main exposed pit a high-angle fault zone, down-dropping basalt on the west from sandy conglomerate on the east, strikes N300E-N400E, is about 20 feet wide, and contained epithermal quartz rich in gold and silver. Rich ore stained strongly by pyrolusite and minor hematite contained free gold as dust, flakes, and wires. The electrum contained 36% silver. No sulfides occur in the
ore. High-grade ore carried hundreds of ounces of gold per ton in narrow veins 1-5 inches wide. One five inch wide vein, assaying 100 ounces of gold per ton, was stoped from the 150 foot level for 75 feet. Total gold production was about 6,000 ounces. Down-faulted basalt in the hanging wall contained a large manganiferous calcite vein about 3 feet wide and 100 feet in length, and carries low values in gold and silver.
Old Wasp Mine. The old Wasp Mine lies about 1,000 feet south of the Mormon Stope on the foot wall of the Mammoth Fault. The ore shoot is unique in the district, occurring in silicified granite which resembles rusty rhyolite. A shear zone, dipping from about 75° to near-vertical, contained fine electrum (gold and about 20% silver). Free gold with minor galena, cerrusite, and malachite occurred central to the ore shoot. In 1983, within 30 feet of the surface, the ore yielded ever 2,500 ounces of gold. The ore shoot
pinched to a narrow vein. An old drift underground intersected the ore shoot on the 1,022 feet level where gold values averaged 0.66 ounces per ton along 40 feet of the drift.
Bluebird Mine. A fault zone, dipping 60°-70° to the west cuts conglomerate and interbedded basalt on the hill immediately south of Goldfield. The fault contained a small elliptical shoot of quartz about 3 feet wide, which was very rich in electrum. The original shaft was 55 feet deep, now 120 feet deep. Production is unknown.
Bull Dog Mine. The Bull Dog Mine lies 1.35 miles west of Goldfield (in the Apache Junction
Quadrangle) dug into a near-vertical fault zone filled with a large manganiferous calcite vein 400 feet in length. The fault separates granite in the hanging wall on the east from granite in the foot wall on the west. The south end of the large calcite vein contained a large shoot of epithermal quartz 45 feet long and 3 feet wide rich in electrum and assaying in gold up to 250 ounces per ton. The quartz locally surrounded by
brecciated volcanic rocks and calcite. Near the surface the ore contained pyrolusite but no sulfides. At 105 feet pyrite was abundant. The vein is fractured and contains slicks, indicating renewed faulting after emplacement. The mine has produced about 6,700 ounces of gold. Other manganiferous calcite veins occur in the vicinity of the mine.
*These radiometric ages have been recalculated using updated decay constants.
14
PART OF THE SUPERSTITION MTS. SW QUADRANGLES, MARICOPA AND PINAL COUNTIES, ARIZONA
by Steven J. Skotnicki and Charles A. Ferguson
Arizona Geological Survey
Open-File Report 95-9
August, 1995
No mention of any tellurides, that I could find.
As for not presenting any theory to support a mesothermal or hypothermal origin for Dutchman ore, there really is no need for me to present such a theory as we have published expert opinion that identifies it as mesothermal. However, if this strikes anyone as impossible or improbable, it should be borne in mind that these are not far different from epithermal veins, the main difference being the depth involved so in general it takes much longer for the deeply buried veins to be exposed by erosion and/or geologic uplift. As these deeper types are commonly found in monzonitic and/or granodioritic intrusives, and these types of rock are present in the Superstitions in several areas including along First Water trail, as well as east and south of the IV ranch. Hence it is not impossible nor improbable. In fact it may well be what Waltz was really referring to in his cryptic comment about the mine being unique in some way. <Paraphrasing> The fact that Waltz's mine has proved so difficult to rediscover actually would be more likely to be the case with a mesothermal or hypothermal vein, for being more deeply buried in the first place, these types often have much less of their ore body exposed by nature than the more common epithermal veins. The mercury vapor test could also be pointed to as evidence in favor of a deeply buried vein as opposed to a near-surface epithermal deposit.
Can we agree to call it "hydrothermal"?
Oroblanco