STORIES - Corundum: the mineral behind ruby and sapphire

The world of gemstones is incredibly diverse. In this blog, we’ll be focusing on corundum. This mineral is one of the hardest known to us, scoring a nine on the Mohs scale of hardness just one step below the most famous mineral, diamond. Its durability makes it an ideal choice for everyday wear.

What is corundum?

Corundum is a mineral formed from pure aluminium oxide. On its own, it is colourless and forms naturally into crystals with pyramid-like tips or hexagonal prism shapes.

It can be found in countries such as Sri Lanka, Madagascar, Thailand, Australia, and Tanzania.

How does this gemstone get its colour?

Colour appears when traces of other elements such as chromium, iron, or titanium are present. These give the gemstone its distinct character, sense of history, and luxurious feel.

The intense red of a ruby comes from the presence of chromium, giving it an association with passion, fire, and royal elegance.

Sapphire, on the other hand, gets its deep blue hue from traces of iron and titanium. What’s especially fascinating about sapphire is that it can be found in many colours: yellow, pink, purple, green, and even colourless (known as leuc sapphire).

A fun fact: only the red variety is called ruby. All other colours of corundum fall under the name sapphire.

Rare varieties

There are some exceptional varieties of corundum. One of them is the padparadscha, a rare pink-orange sapphire, named after the salmon-coloured lotus flower. It’s considered one of the rarest and most cherished gemstones in the world.

Perfect for everyday wear

As mentioned earlier, corundum is among the hardest minerals on Earth. Thinking about a piece of jewellery you’d love to wear every day?
Then a piece featuring a gemstone from the corundum family (like ruby or sapphire) is a perfect and stunning choice.

At byJacky, it’s all about your story. Book an appointment, and together we’ll find the piece that truly reflects your style.