3. Diamond – $55,000 per gram
Long-prized for their beauty and value, diamonds are the most expensive gemstone despite the fact that they’re not the rarest on earth. Diamonds form deep under the earth’s crust through intense pressure and heat, which transform carbon molecules into the hardest gem on earth. Some diamonds have been dated as far back as 3.2 billion years.The high value of diamonds is, of course, a contentious issue as the resource has been known to be exploited. The mineral is commonly found in certain war-torn areas of Africa, where ‘blood diamonds’ can be used as bartering material for illegal weaponry.
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