Sapphires are considered a symbol of honesty, loyalty, purity and trust which is why they are given as a gift between committed partner of these associations. We think of sapphires as blue, though they come in every color of the rainbow: pink, yellow, orange, peach and violet. Padparadscha is a very rare form of sapphire due to its color pinkish orange. Originating from Brazil for the most part. 

The largest source is from Australia’s Queensland, but the most prized come from Myanmar (Burma), Kashmire, and Sri Lanka (Ceylon). The most expensive blue sapphires have a velvitish blue due to the silk inclusions. Most sapphires are heated to bring out the rich color. 

Gemologically, they are corundum growing in hexagonal  habit. The chemical formula is Al2O3, Fe, Ti, and Cr. Their luster is from the fact they are a metallic gemstone.  The variation in color is imparted from the amount of chromium, Titanium and Iron are present. 

The second largest example is available in the Smithsonian National Museum of Natural History in Washington DC. The :Logan brooch weighs 423 carats. Originating from Sri Lanka.