This spectacular AAA-grade Iris Agate slice comes from a rare limb cast deposit in Java, Indonesia—one of the most sought-after sources of fine iris agate in the world. This particular piece is notably thicker than most iris agate slices at 4.8mm, which allows for a deeper, more dimensional play of spectral color without sacrificing the clarity of its light diffraction.

When properly backlit or angled in sunlight, this agate radiates an extraordinary full-spectrum iridescence—known as the “iris” effect—caused by extremely fine, regularly spaced bands of silica that diffract visible light. These ultra-thin layers act as a natural diffraction grating, creating luminous bands of blue, violet, green, yellow, and red across the surface in vibrant, shifting waves.

Formed millions of years ago when mineral-rich waters replaced organic wood material, this limb cast agate preserves the outer shape of ancient tree branches while developing concentric silica banding inside the hollow. Java’s deposits are renowned for their purity, clarity, and exceptional orientation of banding—making it one of the only regions in the world where thick slices can still yield strong iris phenomena.

A mesmerizing specimen for both collectors and lapidaries, this piece bridges natural history, optical wonder, and rare geological formation with elegance and intensity.