The term 'DIAMOND, FOR ONE' can be solved by the crossword solutions GEM (3 letters), PRECIOUSJEWEL (13 letters), and PRECIOUSSTONE (13 letters). A diamond is a GEM, a precious jewel, and a precious stone. It is the hardest naturally occurring mineral on Earth and is composed of carbon atoms arranged in a crystal structure. Diamonds are often used in jewelry and have been valued for centuries for their beauty and rarity.