Periclase Value, Price, and Jewelry Information

“Magnesium Oxide (Periclase),” synthetic, doped with nickel, ~ 5 carats. Photo © Joel E. Arem, PhD, FGA. Used with permission.

Periclase

Periclase has been synthesized in large masses in the laboratory, but these have no market significance. A faceted natural periclase would be a great rarity due to the extreme scarcity of suitable faceting rough. The expected size would be less than 1 carat.

Periclase Information

Data Value
Name Periclase
Colors Colorless, white, gray, yellow, brownish yellow, green, black.
Crystallography Isometric. Crystals octahedral, cubic; commonly as rounded grains.
Refractive Index 1.736
Luster Vitreous.
Hardness 5.5
Fracture Uneven
Specific Gravity 3.56.
Birefringence None.
Cleavage Perfect 1 direction
Stone Sizes I have not seen any faceted gems, but if such gems existed, they would be very small. Transparent grains from Vesuvius might be cuttable, but in general periclase is not known in transparent. large crystals.
Luminescence Pale yellow in LW (Terlingua, Texas).
Luminescence Present Yes
Luminescence Type Fluorescent, UV-Long
Transparency Transparent.
Formula

MgO

Pleochroism

None.

Optics

Isotropic; = 1.736.

Optics: Isotropic; N: 1.736.

Occurrence: Occurs in marbles, due to high-temperature contact metamorphism.

Texas; New Mexico.

Spain; Sardinia; Czech Republic; Slovakia.

Crestmore, Riverside County, California: embedded grains.

Vesuvius, Italy: as glassy grains in the lava rocks.

Nordmark, Sweden: in the Mn mines.

Comments: Periclase has been synthesized in large masses in the laboratory, but these have no market significance. A faceted natural periclase would be a great rarity due to the extreme scarcity of suitable faceting rough. The expected size would be less than 1 carat.

Name: From the Greek peri plus klastos, to break around, in allusion to the cleavage.