Did you know that the first sapphire successfully grown by man was in the late 1800s or early 1900s… apologies for such a wide date range but there are a number of credible sources whose opinions differ!
Whenever it actually was, rubies were successfully synthesized first, before sapphires. If you own a rather nice watch, you may already own synthetic sapphire as the sapphire crystal glass used in watches is colourless synthetic sapphire. If it’s a very nice watch, you may well have synthetic ruby bearings inside too!
Synthetic sapphires have the same physical, chemical and optical properties as natural sapphires – to all intents and purposes they are identical (apart from their inclusions… but that’s a blog post of its own…). You can also find colour-change synthetic corundum which has been used to imitate alexandrite (badly) but it may also be found in antique jewellery, its colour looking just like an amethyst… until you try 2 different light sources!
As well as gemstones, synthetic sapphires are also used in lasers, but the most interesting industrial use I’ve seen is where they are used as windows in the aerospace industry… cosmic!! Sorry, couldn’t resist…