Last updated: November 28, 2021 at 10:30 PM All the Things You Are The birthstone for September is sapphire. Sapphire belongs to the same ore called corundum as rubies, and its composition consists of aluminum oxide (chemical formula Al2O3). The usual color of sapphire is blue, but there are actually many other types, such as green, pink, orange, white, etc. Of these, my favorite is the sapphire, which is considered to be the finest cornflower blue (royal blue). In addition... Read more »

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