Subsoil: a resource
Diamond
The most precious gem is the diamond, made of carbon. The characteristics that make it so valuable are: its hardness, un-alterability, brightness and transparency. The most common diamonds are usually colourless. However the most popular ones tend to have a pale yellow or brown colour. Red, green and blue diamonds are extremely rare and expensive. India is the country where the first deposits were discovered. Now those deposits have been exhausted, while relevant quantities are still present in Brazil and South Africa.
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