Made from tough, maintenance-free, G-10 filament glass cloth/epoxy resin composite matched to the exact colors used by the U.S. armed forces. G-10’s superior impact-resistance, low moisture-absorption properties, and dimensional stability over a wide temperature range mean these grips will not fail, even under the worst weather conditions.
OK, Micarta is a licensed name for a group of fiberglass products, one of which is G-10. G-10, in turn comes in 3 flavors, which are 'regular' G-10, FR4 (fire rated), and CR (cryogenic).
Basically, G-10 is layered woven fiberglass layers, impregnated with epoxy resin. Micarta products also include paper, linen, and canvass Micarta, where-in layers of non-fiberglass materials (such as cotton canvas) are sandwiched in the plastic/epoxy matrix. HTH.