From wikipedia: G-10 is the
toughest of the glass fiber resin laminates and therefore the most commonly used.
Micarta industrial laminates are manufactured in dozens of commercial grades.
Grade designations for glass epoxy laminates are:
G-10, G-11, FR-4,
FR-5 and
FR-6.
End wikipedia quote.
G10 and FR-4 are interchangeable, except where 'fire retardant' (FR) is required. Every laminate material is made by layering a filler: carbon fiber, canvas, cotton, cloth, paper or fiberglass between layers of thermoset epoxy or phenolic resin (micarta), and cured under high heat and immense pressure. All were invented for use as electrical insulators and molded parts for various industries. Micarta was first used by Westinghouse in 1912. In WWI it was used to make aircraft propellers.
All laminates used for knife handles have high strength to weight ratios, in tension, compression and flexion. They are dimensionally stable, chemical resistant, do not absorb water (except micarta), resist wear and are suitable for use in any climate.
My experience is they are all suitable for knife scales and handles. I have knives with scales or handles made of nylon (SAK), micarta, G10, leather, wood, metal, phenolic resin (bakelite) and bone. Micarta is manufactured with several different filler materials: canvas, burlap, linen and paper. I just received two Buck 120 Pro 7-3/8" S35VN blade, 12" overall, with micarta handles. It is one of the best handles I've ever gripped. It is grippy; like it's mildly sticky. I tried to pull it out of my hand, and it was difficult. It's very comfortable against the skin. It readily takes on body heat, so it doesn't feel cold. Micarta is a brand name for many similar laminates.
Paper micarta can be highly polished. Linen is strong, and can be made in many different colors and patterns, to produce striking effects after machining. Canvas micarta is is the strongest, and is the form commonly used for hunting knife handles. IMHO, all things considered, G-10 is the toughtest laminate used for knife handles.