Faculty & Staff Specimens
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Amethyst (SiO2), Llano County, Texas
Locality: Amethyst Hill (?), Llano County, Texas Purple quartz of this quality are rare in the Hill Country Chemical Formula: SiO2 (its violet color to irradiation, iron impurities, and the presence of trace elements) Crystal Class: Hexagonal (Most often as protruding clusters of pyramids on a matrix base, often quite large. Also occurs as tall prismatic crystals, and as short stubby crystals, in drusy aggregates Size: 12.5cm x 5cm x 10 cm Weight: 732 grams Personal Collection of Professor Dr. Mark Helper, Univ. of Texas at Austin
Native Sulfur (S), with Calcite and Anhydrite, Harris County, Texas
Locality: Hockley Salt Dome, Warren Ranch, Harris County, Texas, Elemental Sulfur is common in Salt Domes of the Gulf Coast Chemical Formula: S Crystal Class: Orthorhombic, crystals are usually yellow to yellowish-brown blocky dipyramids, with thick tabular and disphenoidal crystals less common. Diameter of Core: 4 inches In the Jackson Collection (BEG). Additional Information: The assemblage of this sample (massive Anhydrite, Calcite and Sulfur) is common in the cap rocks of salt domes. This large sample was cored by Marathon Minerals in the early 1980's during their exploration for base metal sulfides (lead, zinc and silver).
Native Sulfur (S), with Calcite and Anhydrite, Harris County, Texas
Locality: Hockley Salt Dome, Warren Ranch, Harris County, Texas, Elemental Sulfur is common in Salt Domes of the Gulf Coast Chemical Formula: S Crystal Class: Orthorhombic, crystals are usually yellow to yellowish-brown blocky dipyramids, with thick tabular and disphenoidal crystals less common. Diameter of Core: 4 inches In the Jackson Collection (BEG). Additional Information: The assemblage of this sample (massive Anhydrite, Calcite and Sulfur) is common in the cap rocks of salt domes. This large sample was cored by Marathon Minerals in the early 1980's during their exploration for base metal sulfides (lead, zinc and silver).
Petrified Wood Cross Section, Karnes County, Texas
Purchased from a rock shop, this stunning example of silicified petrified wood was one of several cross sections cut from a specimen purportedly collected in Karnes County, Texas. Specimen Size: 19 x 20.5 x 1.25 inches Specimen weight: 25 lbs. From the personal collection of Eddie Collins, geologist at the Bureau of Economic Geology, University of Texas at Austin.