30 samples of fire agate (SiO2) from Mexican new deposits (State of Aguascalientes, Calvillo and Jesus Maria municipalities) were documented using Raman Microprobe (RMP), Infrared reflection (IRS) Spectroscopy, Scanning Electron (SEM), and Atomic Force Microscopy (AFM). Fire agate, a non-transparent variety with multicolored fire, show a higher degree of organization of homogeneous nano-structure which is built from the ordered accumulation of a mixed nano-spheres of ï¡-quartz and moganite which are characterized by appropriate size (mainly 250-320 nm diameter) for diffraction of visible light. This agate variety present the new natural nano-structure of two silica polymorphs which associated with common agate, that is, a irregular three-dimensional network of heterogeneous ï¡-quartz and moganite spheres less 100 nm or more 320 nm in diameter. This work demonstrates that ï¡-quartz and moganite nano-spheres are the elementary building blocks of this rare variety of agate.
Keywords: fire agate, ï¡-quartz, moganite, nanoparticles, Raman and infrared reflection spectroscopy, scanning electron and atomic force microscopy