Gemstones

Sapphires are precious stones composed of the mineral corundum (aluminum oxide), with a hardness of 9/10 on the Mohs scale. They’re the most popular colored gemstones in the United States. Here are the 21 major sapphire colors and types.

Learn all about the birthstones by month. This informative guide covers the characteristics, colors, value, and beliefs surrounding each birthstone. You’ll also learn how the birthstone tradition started, who decides which month gets what stone, and why some months have multiple gems.

Emeralds are gemstones formed from the mineral beryl. To be called an emerald, a beryl gem must be primarily green, and possess a certain intensity of color. Here are the different types of emeralds you’re most likely to encounter.

Traditionally, only four gemstones in the world are considered precious: diamonds, sapphires, rubies, and emeralds. This guide explores the characteristics of each of the four precious gems, and also looks at the key differences between precious and semi-precious stones.

Rubies are red precious stones formed from the mineral corundum. They can display varying hues and tones of red depending on their place of origin. We’ve compiled a list of the nine most notable types of rubies, with information about their history, characteristics, and value.