11.25 ct TriGem Franklinite Willemite Zincite – USA

The Tri-Gem Series represents one of the most iconic fluorescent mineral associations ever discovered: Franklinite, Willemite, and Zincite from the legendary Franklin–Sterling Hill mining district, New Jersey, USA.

Unlike ordinary collector stones, these highly polished Tri-Gem pieces reveal an entirely hidden world under ultraviolet light. Depending on the wavelength used, especially under 365 nm UV and shortwave UV illumination, the different minerals awaken in spectacular contrast — electric green Willemite zones, glowing Zincite reactions, and deep metallic Franklinite structures combine into a natural fluorescent composition unlike anything else in the mineral world.

Each piece is completely unique. No two Tri-Gem patterns are ever identical.

While this material is famous among serious fluorescent mineral collectors, it is extremely unusual to see it professionally polished and presented as a true collector gemstone. The polishing process itself is highly difficult due to the contrasting hardness and structural composition of the three intergrown minerals.

This 11.25 ct example was carefully selected and polished to maximize both its daylight appearance and its ultraviolet reaction, transforming a historic mineral association into a modern collector object.