Galena (Pb) and Sphalerite (Zn), Hudspeth County, Texas
Minerals: Sphalerite (green/brown) and Galena - silver/grey (base metal sulfides) Location: identified as from the Bonanza Mine, Quitman Mountains County: Hudspeth County, Texas Chemical Formulas: Sphalerite (Zn, Fe)S and Galena (PbS) Crystal Systems: Sphalerite (Isometric hextetrahedral), Galena (Isometric/cubic) Moh's Hardness: Sphalerite (3.5-4), Galena (2.5-2.75) Specimen Size: 3.5 x 3.25 x 2.5 in Specimen Weight: 1.11 kilograms Collection Reference: TMM 1508 Other information: The Bonanza mine is located in the northern Quitman Mountains in southern Hudspeth County, approximately 130km southeast of El Paso, Tx. The northern Quitman Mountains are a volcanic cauldron that has been superimposed across Laramide-deformed Paleozoic and Mesozoic marine strata of the Chihuahua Trough. The cauldron is expressed as a thick, areally restricted sequence of ash flow tuffs encircled and intruded by a composite granitic ring dike with a stock at its northern end. Separating the ring dike from the volcanic pile on the north and east is an arcuate septum of Cretaceous limestone that has been deformed into an anticline (Murry, D.H., 1980). The Bonanza Mine is located in the northern stock. The Bonanza Mine has four levels: 32 m, 50 m, 69 m and 85 m. All are connected by a main shaft and an exploration shaft, and a ventilation shaft opens to the first level. The main shaft is badly caved, and the others are filled with debris. The lower levels reportedly are flooded (Murry). The 1902 Mineral Survey of Texas lists a Bonanza Mine sample assay with 28 ounces of Silver (Ag) per ton and 61.8% Lead (Pb). A more detailed description of the mineralogy of the Bonanza mine vein was captured by McNulty, W.N et al (1971) in the 5th Annual Field Trip Guidebook of the El Paso Geological Society: "The principal ore minerals are galena and sphalerite. Quartz constitutes most of the gangue; comb structure is common, Pyrite is fairly abundant, and a small amount of wulfenite is present in the upper levels. Silver appears to be tied up with the galena, and the sphalerite contains some cadmium. Gold and uranium occur in trace amounts. Chalcopyrite and oxidized copper minerals (malachite and chrysocolla) are sparsely disseminated through the vein material. The vein also contains appreciable amounts of specular hematite, magnetite, altered feldspars, and clay minerals. In the upper levels galena and sphalerite are present in approximately equal amounts, but the sphalerite content increases with depth. The water table stands 200-300 feet below the surface, depending on the topography. The amount of water is relatively small -- about 2 or 3 gallons per minute in the lower levels. Therefore, water presents no great problem in mining; in fact, the water available is an asset for milling. The quartz monzonite is highly altered (kaolinized) in places and does not stand well--especially in the wet, lower levels. " Remember, this was in 1971, the mine has caved in and deteriorated significantly since.
Scheelite (Tungsten Ore), Hudspeth County, Texas
Scheelite in limestone with garnets, hematite, calcite, epidote Location: not listed, but assume to be in the Quitman Mountains associated with an often noted skarn (intrusive contact with host limestone). Chemical formula: Ca(WO4) Crystal system: Tetragonal Left Specimen size: 7 x 5.5 x 3.5 centimeters Right Specimen size: 12 x 4.5 x 5 cm Left Specimen weight: 237 grams Right Specimen weight: 521 grams Collection reference: TMM 701 Additional Information: "The tungsten-bearing mineral scheelite has been known since 1916 in recrystallized sugary limestone beds of the Torcer Formation where it has been metamorphosed on the west side of the Quitman pluton and west of a line projected along the Bonanza fissure (Udden, 1941). According to a report by J. F. McAllister (written commun., 1942), the scheelite is in isolated grains, coarse aggregates, and thin veinlets replacing the limestone. Kock discontinuously mineralized with tungsten was traced for about 700 feet along the contact zone. The principal minerals associated with the scheelite are specular hematite, garnet, epidote, tremolite, pyrite, quartz, calcite, and secondary copper minerals." (from "Geology of the Sierra Blanca Area, Hudspeth County, Texas" Albritton & Smith, USGS Professional Paper 479, 1965.)
Scheelite Fluorescence, Hudspeth County, Texas
Characteristic Fluorescence (short wave) of Scheelite in limestone with garnets, hematite, calcite, epidote Location: not specifically listed, but assume to be in the Quitman Mountains associated with an often noted skarn (intrusive contact with host limestone). Chemical formula: Ca(WO4) Crystal system: Tetragonal Left Specimen size: 7 x 5.5 x 3.5 centimeters Right Specimen size: 12 x 4.5 x 5 cm Left Specimen weight: 237 grams Right Specimen weight: 521 grams Collection reference: TMM 701 Additional Information: "The tungsten-bearing mineral scheelite has been known since 1916 in recrystallized sugary limestone beds of the Torcer Formation where it has been metamorphosed on the west side of the Quitman pluton and west of a line projected along the Bonanza fissure (Udden, 1941). According to a report by J. F. McAllister (written commun., 1942), the scheelite is in isolated grains, coarse aggregates, and thin veinlets replacing the limestone. Kock discontinuously mineralized with tungsten was traced for about 700 feet along the contact zone. The principal minerals associated with the scheelite are specular hematite, garnet, epidote, tremolite, pyrite, quartz, calcite, and secondary copper minerals." (from "Geology of the Sierra Blanca Area, Hudspeth County, Texas" Albritton & Smith, USGS Professional Paper 479, 1965.)
Talc (pink), Hudspeth County, Texas
Mineral: Talc Location: Allamoore Talc District County: Hudspeth County, Texas Chemical Formula: Mg3Si4O10(OH)2 Crystal System: Triclinic Moh's Hardness: 1 Specimen Size: 13.5 x 15 x 4.5 cm Specimen Weight: 2.64 kilograms Produced from 1952 to-date for use in the paint industry.