5.17 Ct. Cabochon Boulder Opal from Australia

This opaque 5.17 carat oval shape multicolor boulder opal measures 14.71 by 10.50 by 4.60 millimeters, and it is presented as a cabochon cut with intense color intensity and an excellent polish. Origin Australia, enhancement doublets. The matrix driven browns of this Australian boulder opal provide a rich, warm tone that sets off electric greens, deep blues, and flashes of red and orange, giving the gem a dramatic contrast and depth that many lighter opals cannot match. Compared to Lightning Ridge black opals, which often show a darker body tone and brooding blues and greens, this boulder opal offers a more textural and landscape like presentation, where the ironstone backdrop enhances the play of color rather than simply darkening it. Compared to Coober Pedy white opals, which tend toward softer pastel hues on a pale body tone, this stone reads as more vivid and saturated, with hue and tone that remain striking even under softer light. Compared to Ethiopian opals, which can exhibit brilliant fire but may be hydrophane and change tone with moisture, the natural ironstone support of this boulder opal stabilizes the hue and sustains intense saturation, making it more reliable for everyday wear.

When compared to Mexican fire opals, which rely on transparent orange and red body colors and generally lack the same play of color, this boulder opal shows a multicolor spectacle that is rare in more uniform fire opals, and the patterning alone carries collectible appeal. As a doublet the piece benefits from a reinforced backing that intensifies the tone and color without the price premium of a solid black opal, creating exceptional value for collectors and designers seeking strong visual impact at a sensible cost. The cabochon cut and excellent polish maximize face up brilliance, and the 5.17 carat weight with generous dimensions makes it a practical focal stone for rings and pendants where its unique hues will command attention. At The Natural Gemstone Company we highlight the balance of beauty, durability, and affordability in this boulder opal, and we recommend it for those who want the unmistakable Australian play of color combined with the rugged, earthy charm of ironstone, offering a distinctive alternative to other famous opal sources.