The hardest mineral belongs to diamond. There are different colors of diamonds, the most famous of which are white and blue. Diamond is one of the most precious Gemstones in the Middle East and has a very high value. The high value of a diamond is due to its high hardness, shiny luster, and high dispersion.
Also, it is completely insoluble in acids and bases and reduces the clarity of diamonds by cracking, breaking, scratching, and cracking. Diamonds are usually formed at a depth of 100-200 km below the ground and a temperature of about 900-1300 ° C and a pressure between 45-60 kbar. Diamonds are mined in Siberia, Australia, Botswana, Brazil, India, and Russia. In Iran, ophiolite belts are among the areas prone to diamond exploration.
In pre-Islamic Iran, not much attention was paid to diamonds. Iranian scientists such as Abu Rihan al-Biruni and Abu Ali Sina have studied this mineral in the Islamic period; the ancient Iranians did not pay much attention to diamonds due to the lack of mines in Iran or nearby lands.