sapphire

Diamond is the hardest natural material in the world. However, it’s also brittle. Scientifically speaking, hardness measures the ability…

The optical properties of minerals attract our eyes and can give a specimen a unique character. However, mineral physical properties are also…

Although gemstone magnetism isn’t a commonly tested gemstone property, it may be useful for making quick separations outside the lab. By Richard…

  Mineral streak testing is fun if you have rough material to spare. It’s not recommended for finished gems, as there’s a good…

Some species of the oxide and hydroxide classes are important ore minerals while others are valuable gemstones. We will explore these diverse…

This article covers eight rare mineral classes not commonly studied in gemology: phosphates, arsenates, vanadates, wolframates, molybdates,…

In crystallography, mineral habits refer to the way crystals form within a specific mineral. In A Guide to Gem Classification, I mentioned that,…

Crystallography explores stunning mathematical concepts you can see in nature and art. In this article, we’ll discuss crystallography…

Pleochroism means “more colors.” Pleochroic minerals show two or three colors when viewed from different angles. This property appears…