Micro-World Gems & Gemology, Fall 2023, Vol. 59, No. 3

Rainy Lakeside City in Peridot


Blade-like magnetite inclusions developed from a healed fracture in a 2.08 ct Burmese peridot resemble a rainy lakeside city. Photomicrograph by Makoto Miura; field of view 1.06 mm.
Blade-like magnetite inclusions developed from a healed fracture in a 2.08 ct Burmese peridot resemble a rainy lakeside city. Photomicrograph by Makoto Miura; field of view 1.06 mm.

Inclusions in gemstones provide useful information regarding their geological origin. A 2.08 ct Burmese peridot containing unique black blade-like inclusions developed from healed fractures (fingerprints), as shown in the figure above. Raman spectroscopy identified these blade-like inclusions as magnetite. Tiny raindrop-like magnetite lamellae were also observed throughout the stone. Such inclusions in Burmese peridot sometimes create four-rayed asterism. According to previous studies, the presence of magnetite lamellae suggests the oxidation or dehydration of olivine by geological processes. This image resembles a rainy lakeside city landscape.

Makoto Miura is supervisor of colored stone identification at GIA in Tokyo.