Nov 17, 2025 · Get to know all you need about diamond – the history, facts, quality factors, treatments, imitations and much more here at GIA.

Established in 1931, GIA is an independent nonprofit that protects the gem and jewelry buying public through research, education and laboratory services.

Diamond’s characteristic chemical composition and crystal structure make it a unique member of the mineral kingdom. Diamond is the only gem made of a single element: It is typically about 99.95 …

The world’s love of diamonds had its start in India, where diamonds were gathered from the country’s rivers and streams. Some historians estimate that India was trading in diamonds as early as the …

May 3, 2024 · Diamond growth may occur somewhat quickly compared to its age, building up a crystal layer by layer over thousands or perhaps millions of years. The subsequent period of mantle …

Nov 24, 2015 · Diamond crystals are brought closer to the Earth’s surface through volcanic activity. Diamonds can be found in shallow alluvial deposits where the crystals settle after being transported …

Diamond Most diamonds formed more than a billion years ago! They form about 100 miles (161 kilometers) below the earth’s surface, where the temperature and pressure are just right. Diamonds …

ここGIAで、ダイヤモンドの歴史、情報、品質を決定する要因、処理、模造石その他多くのことについて、必要な知識の全て ...

Jan 10, 2017 · Incredibly hard, highly refractive, practically impervious to heat, diamond is a crystal form of carbon. But what makes it a real diamond? Find out!

钻石只在地球表面之下大约 100 英里的高温和高压条件下形成。 钻石的碳原子在所有方向上的键合都基本相同。 另一种矿物 - 石墨，同样也仅包含碳，但其形成过程和晶体结构却大不相同。 石墨十分柔 …