Burnet County

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).

Graphite Schist, Burnet County, Texas

Graphite (flake variety) in schist Locality: Burnet County, Texas Chemical Formula: C Crystal System: Hexagonal (dihexagonal dipyramidal) Specimen size: 2.5 in long x 1.5 in deep Specimen weight: 71 grams In the Arthur E. Smith Collection, Wheaton College, Wheaton, Illinois. Additional Information: The Southwestern Consolidated Graphite Company began mining graphite , found in the PreCambrian Packsaddle Schist nine miles northwest of Burnet in the late teens; the mining stopped because of the Great Depression of the 1930s, but began again at the request of the War Production Board in 1942. The Southwest Graphite mines were open pit. A couple of other mining operations were also profitable, better quality graphite was found underground at the nearby Dixie Graphite Company in Llano County. The mine finally closed in the late 1970's.

Monazite, Burnet County, Texas

Monazite, a phosphate containing rare earth elements Locality: Phillips Ranch, Burnet County, Texas Chemical Formula: (Ce,La,Nd,Th)PO4, this is probably a (Ce) Monazite Crystal System: Monoclinic, crystals are usually twinned Specimen size: 2.5 in x 2 in x 1 in Specimen weight: 187 grams In the Arthur E. Smith Collection, on display at Wheaton College, Wheaton, Illinois. Additional Information: Listed as collected by Frank Roberts, from Baringer Hills Minerals who reports that hundreds of monazite-ce specimens have been found buried in the soil around the Cactus Jack Pegmatite that was discovered in 2005 in Burnet County.

Scapolite (with quartz and plagioclase), Burnet County, Texas

Scapolite, typically found where impure limestones have been crystallized by contact with an igneous magma Location: Listed as 10 miles northwest of Burnet County: Burnet County, Texas Chemical Formula: end member Na4Al3Si9O24Cl to end member Ca4Al6Si6O24CO3 Crystal System: Tetragonal Specimen size: 4 x 2.5 x 3 inches Specimen weight: 523 grams In the Jackson School Collection, at the University of Texas at Austin.

Tourmaline (Schorl) in Packsaddle Schist, Burnet County, Texas

Schorl, the Sodium Iron end member of tourmaline group Locality: Town Mountain, Burnet County, Texas Chemical Formula: (Ca,K,Na)(Al,Fe,Li,Mg,Mn)3(Al,Cr,Fe,V)6 (BO3)3(Si,Al,B)6O18(OH,F)4 Crystal System: Trigonal Specimen size: 4.5 in x 3 in 2.5 in Specimen weight: 405 grams In the Arthur E. Smith Collection, on display at Wheaton College, Wheaton, Illinois.