Why this rare gemstone was mistaken for a common ruby for decades

Nature · Published 3 October 2026 Swipe more like this →

In short: Painite is a borate mineral so elusive that for half a century, only two faceted specimens were known to exist. Discovered in Myanmar by Arthur C.D. Pain, the stone was initially misidentified as ruby. Its extreme rarity stems from a fundamental geological quirk: zirconium and boron almost never interact in nature.

The story of painite began in the 1950s when British mineralogist and gem dealer Arthur C.D. Pain encountered the stone in Myanmar. Because of its deep orange-red to brownish-red hue, which bears a resemblance to topaz, it was initially misidentified as ruby. It was only after rigorous analysis that it was confirmed as a distinct mineral species, eventually being named in honor of its discoverer.

Chemically, painite is a complex borate mineral defined by the formula CaZrAl9O15(BO3). Its characteristic color is derived from trace amounts of chromium and vanadium embedded within its structure. While the crystals are naturally hexagonal, they can also appear as euhedral or orthorhombic forms. In some instances, the mineral may lack a crystalline structure entirely, though it is typically found with one. The scarcity of the mineral is fundamentally a result of the rare geological conditions required for zirconium and boron to interact.

For decades, painite held a reputation as one of the rarest minerals on Earth. Until late 2004, the global supply of faceted painite gemstones was limited to just two stones. However, this scarcity has been challenged by recent geological surveys. Extensive exploration in the region surrounding Mogok, Myanmar—the primary area where the mineral is known to occur—has identified several new sites. These discoveries have been subject to vigorous exploration, resulting in the availability of several thousand new specimens, fundamentally shifting our understanding of how rare this mineral truly is.

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