opal

Adamantine. Silky. Greasy? Gemologists and mineralogists use these and other evocative terms to describe luster. This simply means how the surface…

Many factors can contribute to a mineral’s color. However, some minerals can have many different colored varieties, while others only occur…

We tend to take light for granted. It’s such a common thing we experience every day. Rarely do we think of the scientific definition of light…

Most gems form naturally as minerals within the Earth. Most form as crystals, solids whose atoms are arranged in highly ordered repeating patterns…

A gem species is a type of mineral species. Well over 140 mineral species have been utilized as gems. Throughout history, humans have selected these…

Despite some commonalities, there are significant differences between gemology and mineralogy. In this article, we’ll look at the materials…

The silicate subgroups of phyllosilicates and tectosilicates include minerals used in industry and jewelry. Learn how to identify them.

When choosing gemstones for jewelry, it’s crucial to understand more than just how beautiful a stone looks. Gemstone hardness and wearability…

Gems that polarize light and split it into two (or three) different directions are said to be doubly refractive. Birefringence is a measure of a…