Periclase is a magnesium oxide mineral known for its transparent to translucent appearance and vitreous to adamantine luster. Its physical characteristics include a well-formed cubic or octahedral crystal structure, which can vary in size. Periclase is commonly found in metamorphic rocks, such as marbles, and is often associated with minerals like calcite, dolomite, and forsterite.


Periclase has limited industrial uses due to its scarcity in large quantities. However, it has been used as a refractory material in high-temperature applications, such as in the lining of furnaces and kilns, due to its ability to withstand high temperatures without degrading. Its transparent to translucent appearance and high refractive index have also made it of interest to the scientific community for optical research purposes.


Although periclase is not commonly used as a gemstone, its transparent to translucent appearance, high refractive index, and unique crystal structure can make it an attractive specimen for mineral collectors and enthusiasts.


Periclase forms in nature through the metamorphism of magnesium-rich rocks, such as dolomite or magnesite, under high temperature and pressure conditions. During these processes, the original mineral compositions alter, leading to the formation of periclase crystals. This mineral can also form during the cooling of magnesium-rich lava.


Periclase is primarily found in metamorphic rocks like marbles, which form from the alteration of limestone or dolomite under heat and pressure. It can also occur in contact metamorphic zones around igneous intrusions. Geographically, periclase has been found in various locations around the world, including Austria, Italy, Russia, and the United States. These regions are known for their abundance of geological environments suitable for the formation of periclase minerals.


In metaphysical and spiritual practices, periclase is believed to have energizing and purifying properties. The mineral is said to help individuals clear negative energies and emotions, promote clarity of thought, and enhance personal growth. Periclase is also considered a stone of transformation, supporting change and the release of old patterns, habits, or beliefs that no longer serve one’s highest good.

LusterVitreous to adamantine
Hardness (Mohs)5.5
ColorColorless, white, gray, greenish, yellowish
CleavagePerfect in three directions
Specific Gravity3.6 – 3.7