Agate (var. Plume), Brewster County, Texas
Agate (variety Plume, polished) SiO2 (Chalcedony, cryptocrystalline form of Silica or Quartz) Brewster County (collected on Walker Ranch) Shared by the Jornevik Collection (AGMS)
Calcite (Fluorescent), Brewster County, Texas
Calcite (Fluorescent) Locality: Brewster County, Texas Calcite is the most stable polymorph of Calcium Carbonate. Chemical Formula: CaCO3 Crystal System: Trigonal Specimen dimensions: 6in x 5in x 4in deep Specimen Weight: 1.5 kg In the Arthur E. Smith Collection, on display at Wheaton College, Wheaton, Illinois.
Gypsum, var. Selenite "Ram's Horn", Brewster County, Texas
Gypsum, variety Selenite, this curved variety often called “Ram’s Horn” Locality: Brewster County, Texas, Terlingua District Chemical Formula: CaSO4*2H2O Crystal System: Monoclinic Specimen size: 13 in long x 9 in across Specimen weight: 2.9 kilograms On display in the Arthur E. Smith Collection, Wheaton College, Wheaton, Illinois. Additional Information: Incredibly large and stunning specimen, very sculptural curved crystals of translucent selenite with pale pink coating. Most similar specimens in the market were originally acquired back in the late 1950’s and 1960’s, but a specimen this large is unprecedented.
Agate (variety Plume), Brewster County, Texas
Agate (variety Plume, polished) with scale SiO2 (Chalcedony, cryptocrystalline form of Silica or Quartz) Brewster County (collected on Walker Ranch) Shared by the Jornevik Collection (AGMS)
Calcite (Fluorescent), Brewster County, Texas
Calcite (Fluorescent) Locality: Brewster County, Texas Calcite is the most stable polymorph of Calcium Carbonate. Chemical Formula: CaCO3 Crystal System: Trigonal Specimen dimensions: 6in x 5in x 4in deep Specimen Weight: 1.5 kg In the Arthur E. Smith Collection, on display at Wheaton College, Wheaton, Illinois.
Gypsum, var. "Ram's Horn" Selenite, Brewster County, Texas
Gypsum, variety Selenite, this curved variety often called “Ram’s Horn” Locality: Brewster County, Texas, Terlingua District Chemical Formula: CaSO4*2H2O Crystal System: Monoclinic Specimen size: 6 in tall x 3 in across x 2.5 in deep Specimen weight: 436 grams On display in the Arthur E. Smith Collection, Wheaton College, Wheaton, Illinois. Additional Information: Single “ram’s horn” spire, very sculptural curved crystal of white selenite. Most similar specimens in the market were originally acquired back in the late 1950’s and 1960’s.
Agate (variety Plume), Brewster County, Texas
Agate (variety Plume, polished) SiO2 (Chalcedony, cryptocrystalline form of Silica or Quartz) Brewster County (collected on Walker Ranch) Shared by the Jornevik Collection (AGMS).
Calomel (Mercury Chloride), Brewster County, Texas
Calomel (waxy and amber crystal in center of specimen) Locality: Mariposa Mine, Terlingua District, Brewster County, Texas Calomel is rarely found in nature Chemical Formula: Hg2Cl2 Crystal System: Tetragonal Specimen dimensions: 2" x 2" x 1" tall Specimen Weight: 141 grams In the Arthur E. Smith Collection, Wheaton College, Wheaton, Illinois
Nitrate of Potash, Brewster County, texas
Potash is a term used to describe any salts that contain potassium in water soluble form. Nitrate of Potash (or Potassium Nitrate, or saltpeter) has the chemical formula: KNO3 Location: unknown, but listed as Brewster County. An early reference to "Nitrate of Potash" is noted as occurring in seams in Cretaceous Sandstones between Maverick Mountain and the Chisos Mountains by William B. Phillips in Univ. TX BEG Bulletin No. 368 (1914), page 31. Specimen size: 1.25 x 1.25 x 1 inches Specimen weight: 42 grams Collection Reference: TMM 2281
Vesicular Basalt, Brewster County, Texas
Basalt is a fine-grained igneous rock with generally 45-55% silica (SiO2) and less than 10% feldspathoid by volume, and where at least 65% of the rock is feldspar in the form of plagioclase. Dissolved magma gases form bubbles when erupted resulting in this characteristic texture pitted with many cavities (known as vesicles) at its surface and inside. Locality: outcrops along Texas FM 2627 near the Black Gap WMA. Mineralogy: Specimen size: 13.25 com long x 7 cm tall x 4 cm thick Specimen weight: 383 grams Specimen in the Bureau of Economic Geology collection, University of Texas at Austin.
Cinnabar with Gypsum, Terlingua Mercury District, Brewster County, Texas
Cinnabar crystal rhombahedrons on granular matrix with Gypsum spires From the Terlingua Mercury District in Brewster County, Texas Photo Field-of-View: 36.5 x 30 mm Chemical Formula: HgS Crystal System: Trigonal Most common source ore for refining elemental mercury, and is the historic source for the brilliant red or scarlet pigment termed vermilion and associated red mercury pigments. Specimen size: 15 x 7.5 x 11.5 cm Specimen weight: 944 grams Specimen Identification: TMM 3394 Specimen in the permanent collection of the Jackson School of Geosciences, University of Texas at Austin.
Siderite, Brewster County, Texas
Siderite is an Iron Carbonate Locality: found on the Bird Mine dump, Brewster County, Texas Chemical Formula: FeCO3 Crystal System: Trigonal, the color, striated faces and vitreous luster of this sample is typical Specimen size: 3 in x 2 in x 1 in Specimen weight: 203 grams In the Arthur E. Smith Collection, on display at Wheaton College, Wheaton, Illinois. Additional Information: The Bird Mine is described in BEG Report of Investigations 145 on the Silver-Copper-Lead deposits of the Trans Pecos area as a Lead-Silver Breccia Pipe.
Vesicular Basalt, Brewster County, Texas
Basalt is an aphanitic (fine-grained) igneous rock with generally 45-55% silica (SiO2) and less than 10% feldspathoid by volume, and where at least 65% of the rock is feldspar in the form of plagioclase. Dissolved magma gases form bubbles when erupted resulting in this characteristic texture pitted with many cavities (known as vesicles) at its surface and inside. Chemically this is actually a Trachyandesite. Locality: outcrops along Texas FM 2627 near the Black Gap WMA. Mineralogy: Little or no free quartz, dominated by alkali feldspar and sodic plagioclase along with one or more of the following mafic minerals: amphibole, biotite or pyroxene. Specimen size: 12.5 cm long x 9 cm tall x 5 cm thick Specimen weight: 578 grams Collection ID: Specimen in the permanent collection of the Jackson School of Geosciences, University of Texas at Austin.
Cinnabar, Brewster County, Texas
Cinnabar, a Mercury Sulfide Locality: Terlingua District, Chisos Mountains, Brewster County, Texas Chemical Formula: HgS Crystal System: Trigonal, but typically found in a massive, granular or earthy form and bright scarlet to brick-red in color. Specimen size: 4.75 in x 4 in x 2 in Specimen weight: 580 grams Additional Information: Today Brewster County has a population of less than 10,000, but from the turn of the 20th century through World War II, the Terlingua Mining District was a boom town due to the extraction of cinnabar in the Chisos Mountains.