Birthstone for March. Hardness is 7.5 - 8. It varies from pale yellow to golden yellow to dark orange. Hardness is 7. Diamonds are the hardest natural substance with a hardness of 10.
Colors can range from colorless to black.
Colored diamonds are much more rare and expensive. Birthstone for April. Almost all emeralds contain inclusions and fractures. Emeralds of fine clarity and color are expensive. May. Hardness is 7.5 - 8.