Rocks glassy

Perlite consisting of glassy crushed and heat-expanded rock from volcanic origin. 

White, A. F. (1983). Surface chemistry and dissolution kinetics of glassy rocks at 25 . Geochim. Cosmochim. Acta 47,805-815. 

There are two principal sources of reliable partitioning data for any trace element glassy volcanic rocks and high temperature experiments. For the reasons outlined above, both sources rely on analytical techniques with high spatial resolution. Typically these are microbeam techniques, such as electron-microprobe (EMPA), laser ablation ICP-MS, ion-microprobe secondary ion mass spectrometry (SIMS) or proton-induced X-ray emission (PIXE). 

Summarizing the stmctural data described above and conditions of substances forming we conclude the same carbon stmctures may be formed at extremely various P-T-conditions by different mechanisms as glassy-carbon is produced at temperatures 2000-3000°C, but natural shungite at the conditions of sedimentary rocks (no more than 300°C). 

Tektites Glassy rocks that range up to a few centimeters in length. Formation is thought to have been a result of meteorite impacts that liquefied and ejected molten crustal rocks. As the ejecta feU back to Earth, they cooled and froze into teardrop and dumbbell shapes. Small tektites are called microtektites. 

Melson, W. G. Thompson, G. 1973. Glassy abyssal basalts, Atlantic sea floor near St Paul s rocks petrography and composition of secondary clay minerals. Geological Society of America Bulletin, 84, 703—716. 

KELLER (W.D.), 1963. Hydrothermal kaolinitization (endellitization) of volcanic glassy rock. Clays and Clay Min. 10, 333-43. 

Noble, D.C., Ressel, M.W. and Connors, K.A. (1998) Magmatic As, Sb, Cs and other volatile elements in glassy silicic rocks. Abstracts with Programs. The Geological Society of America, 30(7), 377. 

Pyroclastic rocks include scoria and pumices, which show variably por-phyritic textures with dominant leucite phenociysts and minor clinopyrox-ene, some mica, and rare olivine, set in a microcrystalline to glassy matrix that has been generally affected by strong secondaiy processes, with abundant zeolites and clay minerals (Fomaseri et al. 1963 Trigila et al. 1995). Accessory phases include Fe-Ti oxides, apatite and rare garnet. 

Etruschi seamount. Basaltic fragments about 0.1 Ma old have been recovered from this site (Keller 1981). The rock is mostly glassy with a few small grains of olivine and acicular plagioclase crystals. 

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