18.97 Ct. Cabochon White Opal from Australia

This translucent grey pear shape opal presented by The Natural Gemstone Company is a rare and substantial specimen, weighing 18.97 carats, with precise dimensions of 26.80 x 17.10 x 8.20 mm. This stone is a white opal classified by laboratory color as grey, and it has been IGI certified, providing independent verification of its stated characteristics. The cabochon cut preserves and enhances the vivid play of color that defines fine opal, and the excellent polish produces smooth reflections and a pleasing hand feel. The opal shows medium intense color intensity and a multi color display that is particularly attractive for collectors and designers who seek both aesthetic beauty and geological authenticity. No enhancement has been performed on this gem, and its Australian origin adds provenance that experienced buyers recognize for quality and historical value.

From a gemological perspective this opal checks key grading boxes that informed buyers use to assess quality. The lab color classification as grey indicates a light to medium body tone that acts as an excellent canvas for play of color. In white opal the lighter body tone allows broad spectral flashes to appear across the stone, and in this example the translucency enhances that effect by letting light penetrate and scatter internally. The cabochon cut is the traditional and optimal shaping for opal, maximizing the surface area and curvature to reveal shifting color patches as the stone is moved in light. The medium intense color intensity means colors are easily visible in typical lighting, while the multi color palette includes warm red and orange flashes alongside greens and occasional blues, creating a balanced and dynamic visual effect. The excellent polish ensures that there is minimal surface disruption to interrupt the play of color, preserving both brilliance and tactile quality.

Clarity is graded as very slightly included when evaluated at eye level, a designation that communicates that inclusions are present but do not detract from the overall appearance or structural integrity of the stone under normal viewing. For opal, inclusions can be natural growth textures or minute potch areas, and in this piece they are subtle enough that the opal’s play of color remains the dominant visual feature. Because the stone is unenhanced and has been certified by IGI, buyers can be confident that the clarity assessment is accurate and that no filling or dyeing has been used to alter appearance. The IGI certificate is a meaningful assurance, as it standardizes terminology and measurements, confirming weight, dimensions, shape, cut style, polish quality, origin, and treatment status. Origin from Australia is particularly noteworthy because Australian opal fields are historically and currently among the world’s most respected sources for opal with strong play of color and stable material quality.

For an educated buyer the value proposition of this opal is clear in several technical and experiential terms. The weight of 18.97 carats is significant for opal, as larger stones with consistent play of color become increasingly rare and sought after. The combination of a translucent body, medium intense color intensity, and a multi color pattern that includes desirable red and green flashes increases market desirability, because reds and intense greens typically command premium interest among connoisseurs. The pear shape is versatile for high end jewelry applications, especially as a central pendant or a dramatic drop in a custom ring, and the cabochon style optimizes the optical properties that collectors prize. Natural, unenhanced material from a reputable source and supported by an IGI report is preferred by experienced buyers who value both lapidary integrity and long term durability as opposed to treated or composite stones.

Practical considerations for use and purchase are important and we provide guidance tailored to informed clients. The opal’s size and shape make it ideal for a bespoke pendant setting in gold or platinum that protects the stone while allowing maximum light exposure to enhance play of color. Because opal is relatively soft compared to other gem materials, we recommend settings that cushion the girdle and avoid exposure to hard knocks, and we advise against ultrasonic cleaning or harsh chemicals, recommending gentle cleaning with a soft cloth and mild soapy water. The IGI certificate will be included with the sale from The Natural Gemstone Company, and we are available to provide high resolution images and video to demonstrate the color play under varied lighting conditions. For clients considering acquisition as a collector’s piece or as the centerpiece of a signature jewelry commission, this opal represents a blend of scientific verifiability and visual appeal that aligns with the criteria experienced buyers use to assess quality and future desirability.