Much like emeralds, the only variance in rubies is in the hues available. They can be more red or pink, more opaque, heavily included, etc.

I like the classic red hues but also like the opaque, cabochon varieties. I also like setting rubies in yellow gold as it brings out the richness of the stone.

A fun fact on rubies, they are from the same family as sapphires! And, rubies were often referred to as the king of gemstones for being favoured by nobility.