Diamonds are slightly yellowish, and in this general color range, those most approaching absolute lack of color are most prized. However, brightly colored diamonds are much rarer and more expensive. The deep blue Hope diamond and blue Eugenie diamond, both in the Smithsonian collection, are among the most famous examples. Diamonds are renowned as a material with superlative physical qualities. The name diamond is derived from the ancient Greek (adámas) which means unbreakable, They have been treasured since their use as religious icons in ancient India. The diamond's usage in engraving tools also dates to earliest human history. Many diamonds come from central and southern Africa. Also diamonds have been discovered in Canada, India, Russia, Brazil, and Australia.