Here is a fact that surprises almost everyone. A ruby and a sapphire are, scientifically speaking, the same mineral. They are siblings, and the only real difference is a matter of colour.
One mineral, two names
Both stones are corundum, a crystal made of aluminium and oxygen. In its pure form, corundum is colourless. It is the trace elements that sneak in during formation which give it colour.
A little chromium turns it red, and that red corundum is called a ruby. Corundum in almost any other colour is called a sapphire. Blue is the one we all picture, caused by traces of iron and titanium, but sapphires also come in pink, yellow, green, purple and orange, as well as colourless.
Where the line gets blurry
If sapphire is every other colour, you might wonder where red ends and pink begins. This is a genuinely debated point. A pink sapphire with a little more chromium can tip into ruby territory, and different laboratories draw the line in slightly different places.
That is why a stone sold as a ruby in one place might be called a pink sapphire in another, and why it pays to ask which lab graded it. There is also the rare padparadscha, a delicate pinkish orange sapphire that is among the most prized of all.
Why this matters when you buy
Because they share the same make-up, rubies and sapphires share the same strength. Both score 9 on the Mohs hardness scale, second only to diamond, which makes them excellent for rings you plan to wear every day. Where they differ is in price and availability.
Fine rubies are scarcer, and top quality red stones often cost more per carat than sapphires of comparable size. A sapphire can also be a brilliant way to get a coloured gemstone ring on a smaller budget, particularly in less common shades.
Choosing between them
Pick the colour that you cannot stop looking at. If you love the drama of red, a ruby is the gem for you. If you want more choice, from classic blue to soft pink and yellow, sapphire gives you a whole palette.
Visit Azzallure to see rubies and sapphires side by side, and find out which sibling suits you best.