Diamond (gemstone) to help authenticate Canadian diamonds. This is a very stringent tracking system of diamonds and helps protect the 'conflict free' label of Canadian diamonds. Currently, gem production totals nearly of cut and polished stones annually, and over of mined diamonds are sold for industrial use each year, as are about of synthesized diamond. Diamond (gemstone) A diamond (from the "adámas", meaning "unbreakable", "proper", or "unalterable") is one of the best-known and most sought-after gemstones. Diamonds have been used as decorative items since ancient times; some of the earliest references can be traced to 25,000 - 30,000 B.C. The hardness of
Kimberlite tailings performance of fixed-bed kimberlite tailings was studied and the adsorption capacity was found to be 0.27 mg/g of adsorbent. Film diffusion was found to be the rate-limiting factor for the removal of arsenic by kimberlite tailings. Adsorption of arsenic was found to be pH dependent and higher removal efficiencies were observed near neutral pH range. The arsenic uptake increased with increase in adsorbent dose. Spent kimberlite tailings could be regenerated with dilute NaOH. The proposed treatment methodology was applied to the groundwater samples collected from various places of North 24-Parganas district situated in West Bengal, India. The samples were analyzed