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- COMETS: 1. Achondrites (Basalt/Silicate non-chondritic stones); with a 3-4 grams/cc density, and comprising about 8% of observed falls. These formed in the outer and crustal layers of the asteroid. 2. Siderolites (Stony-Irons); with a 5-7 grams/cc density, and comprising about 2% of observed falls. These formed a thin layer between the core and outer layers of the parent bodies. They generally consist of round, translucent green crystals of olivine imbedded in a matrix of iron. 3. Siderites (Irons); with a 7.9 grams/cc density, and comprising about 6% of observed falls. These are the remains of the core of a differentiated asteroid, and show signs of extremely slow cooling (1-10 deg C per million years), and extremely high shock stresses, presumably from collisions. These meteorites weather so well once on the ground, they make up 54% of all meteorite finds despite their small percentage of the fall population. * Cometary meteoroids: ~95% * Chondritic meteoroids: ~5% * Non-chondritic meteoroids: <1% * Cometary meteoroids: 38% o Type IIIb fireballs, low density comets: 9% o Type IIIa fireballs, high density comets: 29% * Chondritic meteoroids: 62% o Type II fireballs, Carbonaceous Chondrites: 33% o Type I fireballs, Ordinary chondrites: 29% * Non-chondritic meteoroids: <1% o No fireball class * Cometary meteoroids: 0% * Chondritic meteoroids: 84% o Carbonaceous chondrites: 4% o Ordinary chondrites: 80% * Non-chondritic meteoroids: 16% o Achondrites: 8% o Siderolites: 2% o Siderites: 6% * Cometary meteoroids: 0% * Chondritic meteoroids: 37% o Carbonaceous chondrites: <1% o Ordinary chondrites: 37% * Non-chondritic meteoroids: 63% o Achondrites: 3% o Siderolites: 6% o Siderites: 54% Ceplecha, Z., (1985). "Photographic Fireball Networks". Astronomical Institute of the Czechoslovak Academy of Sciences, 251 65 Ondrejov Observatory, Czechoslovakia. Ceplecha, Z., (1985). "The Valec Fireball and Predicted Meteorite Fall". Astronomical Institute of the Czechoslovak Academy of Sciences, 251 65 Ondrejov Observatory, Czechoslovakia. Ceplecha, Z. (1991). "Meteors depend on Meteoroids", Proceedings of the IMC 1990, Violau.IMO, Veitsbronn, Germany, (p.13-21). Borovicka, J., (1993). "A fireball spectrum analysis", Astron. Astrophys. 279, 627-645. Hey, M. H., & Rea, D. G., (1986), "Solar System / Meteors," Encyclopedia Britannica (Vol 27, pg. 587). McKinley, D. W. R., (1961). "Meteor Science and Engineering". New York: McGraw-Hill Book Co. Meisel, D. D., (1990). "Meteor", McGraw-Hill Encyclopedia / EST 7th Ed. Meisel, D. D., Getman, V., Mathews, J., Jacobs, S. C., and Roper R., (1995). "Bolide Aida: Death of an Aubrite Meteoroid," Icarus (116, 227-255). Nininger, H. H., (1972). "Find a Falling Star". New York: P. S. Erikson. Norton, O. R., (1994). "Rocks from Space". Missoula: Mountain Press Publishing Co. (449 p.) Pugh, R. N., (1995). "The Diamond Lake Fireball of March 28, 1994", Meteor News, No. 110 (Fall 1995).