A Sri Lankan gem company claims it has discovered the world's largest single natural blue sapphire, a 683-pound gemstone that it plans to auction after obtaining an official valuation. A 310 kilograms ...

Forbes contributors publish independent expert analyses and insights. David Bressan is a geologist who covers curiosities about Earth. Jun 26, 2025, 02:26pm EDT Jun 27, 2025, 05:34am EDT A medieval ...

Sapphire is a corundum gemstone that has meaning, properties, and uses. Corundum gemstones are the crystalline form of aluminum oxide with traces of iron, titanium, vanadium, and chromium. Sapphire is ...

Douglas, Isle of Man, Jan. 24, 2023 (GLOBE NEWSWIRE) -- Synthetic sapphire, also known as Corundum, is a manufactured gemstone. It has the same chemical composition as a natural sapphire. Synthetic ...

We're back in the museum for this week's episode of Mineral Monday to learn about the mineral corundum. While you may not know the mineral itself, you definitely know two of its crystal structures.