Corundum (ruby and sapphire) is relatively hard—9 on the Mohs scale. It has excellent toughness and no cleavage, which is a tendency to break when struck. This makes it a great choice for rings and other mountings subject to daily wear. Ruby ranks 9 on the Mohs hardness scale, so it's an effective jewelry stone.

How do you know if a ruby is real?

Use the ruby to scratch a hard and yet smooth surface, such as a piece of glass. If there is a streak of red color left behind on the surface, then it is clear that your stone is a fake. A real ruby will never leave color in that way.

Do rubies crack easily?

Rubies are extremely hard gemstones, with a 9.0 Mohs hardness rating, and they can generally hold up well even if they have small cracks on the outside. ... Either way, if you decide to wear the gemstone do not expose the stone to any hard knocks or blows and do not use an ultrasonic cleaner to clean the gemstone.