Direct Diamond Network

Can you guess the identity of this rare 63.17-carat bi-color gem?

This crystal shows a pinkish-orange core surrounded by a gray-blue rim—visually reminiscent of watermelon tourmaline. GIA’s Bangkok laboratory performed advanced testing including Raman spectroscopy and X-ray fluorescence, to reveal this gem’s identity.

This testing revealed it to be dumortierite—a rare aluminum borosilicate mineral known for its vivid color and strong pleochroism. Perfect crystals are uncommon, making this large, colorful, well-formed specimen among the most significant dumortierite crystals documented to date.

Learn more about this stunning crystal in a recent issue of G&G: https://www.gia.edu/gems-gemology/fall-2025-lab-notes-prismatic-bicolor-dumortierite-crystal?utm_campaign=g-g&utm_content=1773082320&utm_medium=organic-social&utm_source=facebook

While best known for its deep, wine-red hue, garnet, January’s birthstone, is actually a family of gems that spans vivid greens, warm oranges, rich purples and even color-change varieties.

Garnet has been treasured for thousands of years as a symbol of strength and vitality and has adorned many civilizations across history. Egyptian pharaohs wore red garnet necklaces, Roman officials used garnet intaglios to seal important documents and Victorians loved garnet jewelry, importing large amounts of garnet from Bohemia (today’s Czech Republic).

More recent discoveries of demantoid, spessartine and tsavorite have broadened the garnet family’s appeal, keeping this classic gem group at the forefront of jewelry design and collector interest. What’s your favorite garnet color?

Learn more about January’s birthstones on our website: https://bit.ly/49450ft