Kristal Kuarsa Dari Karang Tengah Wonogiri , Analisis Data Inklufi Fluida dan Petrografi

Volcanic tertier sediment and intense mineralisation dominantly on Southern Mountain. At Karangtengah,Wonogiri regency there are white to purple quarst crystal with comb texture and useful for gemstone. Field observation choose in gemstone indicated area especially at Karangtengah. Petrography and fluid inclusion analysis has conducted. Megascopycally, Quarst crystal with comb texture and ideal bipyramidal stucture. Petrography, there is feathery texture between euhedral quarst. Based on fluid inclusion analysis; melting point (Tm) between (-1.1) – (- 1.6) 0 C, 2.0 – 2.9 persen Wt NaCl, crystalisation of quarst between 303.0 – 759.1 m depth, homogenation temperature (Th) 230 – 280 0 C at 27.6 – 63.4 bar pressure. From field and laboratory data analysis; crystalisation of quarst at crystalline superzone, lower boiling level, from supersaturated silica hydrotermal fluids, slowly cooled and minimally 1118 m uplifted. Karangtengah Quarst crystal useful for ornamental stone, gemstone material and mineralisation guidance zone. International Conference Earth Science And Technology Yogyakarta 6-7 August 2009, T. Geologi UGM