AGMS - Austin Gem & Mineral Society
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 Crystals, Burnet County, Texas
Calcite Crystals on Limestone Locality: Quarry, Burnet County, Texas Calcite is the most stable polymorph of Calcium Carbonate. Chemical Formula: CaCO3 Crystal System: Trigonal (Specimen example of scalenohedron and modified scalenohedron crystals) Specimen dimensions: 10 in tall, x 7 in wide x 7 in deep Specimen Weight: 6.5 kg Shared by the Pulliam Collection (AGMS).
Petrified Wood Cabachon (with scale), Karnes County, Texas
Beautiful cabachon featuring a variety of agatatized petrified wood from Karnes County, Texas that has been dubbed "Shrinkwood". This cabachon was cut and polished by Richard Dorsey, a member of the Austin Gem and Mineral Society. Additional Information: Shrinkwood is a local Texas name given to petrified wood that has been partially decomposed and fractured and then resealed with more silica. In its most perfect form, the fractured sections of wood are almost perfect hexagons giving it the scientific name, "hexagonally fractured petrified wood". In some cases the brecciated sections retain the original wood pattern and in others the original pattern is barely discernible.
Topaz (river worn), Mason County, Texas
Topaz, typical rounded specimens collected in Mason County, Texas Chemical forumula: Al2SiO4F Crystal System: Orthorhombic Specimen weight: 8 grams (total, all 4 crystals) Specimen size: Top left (brown crystal) long dimension = 15 mm, bottom right (yellow crystal) long dimension = 13 mm From the Middleton Collection (AGMS member).
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)
Celestite, Travis County, Texas
Celestite (or Celestine) a Strontium Sulfate Locality: Travis County, Texas (Bull Creek) Chemical Formula: SrSO4 Crystal System: Orthorhombic Specimen displays classic elongated dipyramidal shape. Specimen size: 3.5 in long x 1.5 in across Specimen weight: 373 grams Shared by the Pulliam Collection (AGMS). Additional Information: Named for its delicate blue color, Celestite is the primary source for strontium, which is used in metal alloys and fireworks. This crystal was found in loose clay along Bull Creek back in the 1960's.
Petrified Palmwood Cabachon Selection - State Stone of Texas
Beautiful Texas shaped cabachons featuring a variety of agatatized palmwood, probably from from east Texas counties, cut in a number of orientations to show wood grain. These cabachons were cut and polished by Adolph Krchnak, a member of the Austin Gem and Mineral Society. Additional Information: Specimens from the Oligocene epoch (34 - 23 mya) can be collected from many scattered sites in east Texas and western Louisiana. Fossils found near fossil palmwood include corals, sponges, and mollusks, indicating that the palms grew along prehistoric beaches. For millions of years, the Gulf Coast shoreline has been moving farther south. Petrified palmwood includes a group of fossil woods that contain prominent rod-like structures within the regular grain of the silicified wood. Depending upon the angle at which they are cut by fracture, these rod-like structures show up as spots, tapering rods, or continuous lines. The rod-like structures are sclerenchyma bundles that comprise part of the woody tissues that gave the wood its vertical strength.
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).
Celestite, Travis County, Texas
Celestite (or Celestine) with scale, a Strontium Sulfate Locality: Travis County, Texas (Bull Creek) Chemical Formula: SrSO4 Crystal System: Orthorhombic Specimen displays classic elongated dipyramidal shape. Specimen size: 3.5 in long x 1.5 in across Specimen weight: 373 grams Shared by the Pulliam Collection (AGMS). Additional Information: Named for its delicate blue color, Celestite is the primary source for strontium, which is used in metal alloys and fireworks. This crystal was found in loose clay along Bull Creek back in the 1960's.
Llanite (or Llanoite), Llano County, Texas
Llanite is an intermediate grain size Rhyolite, noted for its unusual coloration consisting of bright blue quartz and orange phenocrysts of microcline set in a fine grained grey to dark matrix Locality: outcrops along Texas State Highway 16 north of Llano, Texas Mineralogy: Quartz, microcline and plagioclase feldspars, biotite, fluorite, apatite and traces of magnetite, ilmenite and zircon Specimen size: 5.5 in long x 2-4 in wide x .375 in thick Specimen weight: 160 grams Shared by the Downs Collection (UT).
Petrified Palmwood Cabachon Selection (with scale) - State Stone of Texas
Beautiful Texas shaped cabachons featuring a variety of agatatized palmwood, probably from from east Texas counties, cut in a number of orientations to show wood grain. These cabachons were cut and polished by Adolph Krchnak, a member of the Austin Gem and Mineral Society. Additional Information: Specimens from the Oligocene epoch (34 - 23 mya) can be collected from many scattered sites in east Texas and western Louisiana. Fossils found near fossil palmwood include corals, sponges, and mollusks, indicating that the palms grew along prehistoric beaches. For millions of years, the Gulf Coast shoreline has been moving farther south. Petrified palmwood includes a group of fossil woods that contain prominent rod-like structures within the regular grain of the silicified wood. Depending upon the angle at which they are cut by fracture, these rod-like structures show up as spots, tapering rods, or continuous lines. The rod-like structures are sclerenchyma bundles that comprise part of the woody tissues that gave the wood its vertical strength.
Agate (variety Balmorhea Blue), Reeves County, Texas
Agate (variety Balmorhea Blue, polished) SiO2 (Chalcedony, cryptocrystalline form of Silica or Quartz) Reeves County Shared by the Jornevik Collection (AGMS).
Celestite Crystals, Travis Couny, Texas (Bull Creek)
Celestite (or Celestine) is a Strontium Sulfate Locality: Travis County, Texas (Bull Creek) Chemical Formula: SrSO4 Crystal System: Orthorhombic Specimens display variety of crystal forms, including classic elongated dipyramidal shape. Largest specimen size: 3.5" long x 1.5" across Largest specimen weight: 373 grams Shared by the Pulliam Collection in Texas. Named for its delicate blue color, Celestite is the primary source for strontium, which is used in metal alloys and fireworks. Thess crystals were found in loose clay along Bull Creek back in the 1960's.
Petrified Wood, Terrell County, Texas
Petrified Wood, with end Polished Locality: Found in a canyon south of Sanderson, in Terrell County, Texas Shared by the Middleton Collection (AGMS).
Sulfides (Base Metal), Hockley Salt Dome, Harris County, Texas
Locality: Hockley Salt Dome, Harris County, Texas Mineralogy: Marcasite, pyrite, sphalerite, galena, acanthite and barite have been identified in the calcite and anhydrite zones in the cap rock of the Hockley Salt Dome (Kyle and Agee, 1988). Specimen size: quarter slice of 8 inch core, 4.75 in long x 3.25 in wide x 3.5 in deep Specimen weight: 1.1 kilograms Shared by the Murphy Collection (AGMS). Additional Information: In the polished section of this specimen alternating layers of calcite and anhydrite can be seen, the sulfide ore minerals concentrated in the anhydrite-rich zones.
Agate (variety Balmorhea Blue), Reeves County, Texas
Agate (variety Balmorhea Blue) with scale SiO2 (Chalcedony, cryptocrystalline form of Silica or Quartz) Reeves County Shared by the Jornevik Collection (AGMS).
Gypsum, var. Selenite , Bastrop County, Texas
Gypsum, variety Selenite with "fishtail" habit Locality: Along Pin Oak Creek, Bastrop County, Texas Chemical Formula: CaSO4 * H2O Crystal System: Monoclinic Specimen size: 4.125 in x 2.25 in .75 in Specimen weight: 23 grams Shared by the Middleton Collection (AGMS).
Petrified Wood Cabachon, Karnes County, Texas
Beautiful cabachon featuring a variety of agatatized petrified wood from Karnes County, Texas that has been dubbed "Shrinkwood". This cabachon was cut and polished by Richard Dorsey, a member of the Austin Gem and Mineral Society. Additional Information: Shrinkwood is a local Texas name given to petrified wood that has been partially decomposed and fractured and then resealed with more silica. In its most perfect form, the fractured sections of wood are almost perfect hexagons giving it the scientific name, "hexagonally fractured petrified wood". In some cases the brecciated sections retain the original wood pattern and in others the original pattern is barely discernible.
Barite (blue) on Calcite, Karnes County, Texas
Barite on Calcite and Limestone Matrix Scale: Large crystal top right is 1.25 cm across Chemical Formula: BaSO4 Crystal System: Locality: Karnes County, TX (Uranium district) From the Cherepon Collection.
