The term 'Key Material' can be broken down into three crossword solutions: EBONY, IVORY, and CORAL. EBONY is a hard, heavy, and dark wood that is often used to make furniture and musical instruments. IVORY is a hard, white material that is obtained from the tusks of elephants and is often used to make jewelry and sculptures. CORAL is a hard, calcium-based material that is formed by marine organisms and is often used to make jewelry and decorations.