Geopolymer synthesis with the use of phyllite L.G. de A. Melo, F.J. da Silva, and Thaumaturgo C. Instituto Militar de Engenharia, Rio de Janeiro, RJ Products that are environmentally friendly have gained an important role in modern world. Portland cement is one of the most important materials in global economics, but also emits CO2 into the atmosphere, one of the gases responsible for the Green House Effect. With one of its applications as a substitute for Portland Cement, geopolymer is an inorganic polymer that not only does not emit CO2, it also can use a wide variability of starting materials, such as industrial residues or largely available minerals in the earth’s crust. Geopolymer is made basically of a source of solid aluminosilicate mixed with a highly alkaline solution. Phyllite, a highly available and cheap rock, was used for the first time in this product, as a parcial substitute of metakaolin, source of solid aluminosilicate widely used in this technology. The product was synthesized with various percentages of phyllite and evaluated through tests of compressive strength. Keywords: geopolymer, compressive strength, green technology Work supported by FAPERJ. [1] J. Davidovits. Journal of Thermal Analysis. 37, 1633 (1991). [2] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS, ABNT NBR 7215/96 (1996) [3] V. F. F. Barbosa, Síntese e caracterização de polissialatos, DsC. Thesis, IME, Rio de Janeiro, 1999. [4] A.L.R. MORETO, Características química, mineralógica e tecnológica dos filitos da região de Itapeva-SP empregados na indústria de cerâmica, M.Sc. Dissertation, UFPR, Curitiba, 2006. [5] P. Duxson, A. Fernandez-Jimenez, J.L.Provis, G.C. Lukey, A. Palomo, J.S.J. van Deventer, Journal of Materials Science. 42, 2917 (2007) Melo_lis7@hotmail.com; Instituto Militar de Engenharia, Seção de Engenharia Mecânica e de Materiais, Praça General Tibúrcio, 80, Praia Vermelha, 22190-270, Rio de Janeiro, RJ, Brazil