DESCRIPTION: This exceptional Australian Boulder Opal from Queensland immediately stands out through a remarkably concentrated ribbon of precious opal running longitudinally through the specimen. Rather than presenting colour as isolated surface flashes, the play of colour follows a clearly defined internal seam, creating a vivid luminous pathway through the pale opaline body. The dominant chromatic expression is an intense combination of electric green, neon green, aqua blue and vivid blue, accompanied by violet and subtle lilac flashes that emerge as the specimen is rotated. Green is particularly powerful, repeatedly igniting across the central colour band with extraordinary brightness, while cooler blue and violet tones appear between the brighter areas and give the optical structure considerably greater depth. One of the most attractive characteristics of the piece is the continuity of the precious opal seam. The colour does not appear as a single isolated patch, but extends through much of the length of the specimen in a ribbon like formation. Individual sections of this seam display irregular cellular, shard like and mosaic structures, producing multiple small colour fields that activate independently under changing angles of illumination. The surrounding opaline material ranges from milky white to pale bluish translucent, creating a soft neutral frame around the intensely coloured central seam. This contrast is particularly effective because the lighter body allows the vivid green and blue flashes to remain clearly separated and exceptionally luminous rather than being visually absorbed by a dark matrix. Its natural freeform morphology is elongated and angular, with a pronounced taper towards one extremity and a thicker basal section. Several surfaces retain natural host material and earthy matrix traces, preserving the geological character of the specimen and making the relationship between precious opal and its original formation environment clearly visible. Queensland is internationally recognised as the principal source of Australian Boulder Opal, where precious opal develops within fractures, seams and cavities associated with iron rich sedimentary host rocks. This specimen preserves that characteristic seam style particularly well, combining a concentrated ribbon of vivid play of colour with a natural freeform morphology and strong geological character. SPECIFICATIONS: • Weight: 0.25 g • Weight in carats: 1.25 ct • Dimensions: 10 × 6 × 4.5 mm • Origin: Queensland, Australia • Mineral identification: Natural Precious Boulder Opal • Variety: Boulder Opal • Chemical composition: SiO₂ · nH₂O • Structure: Amorphous hydrated silica with play of colour produced by diffraction within ordered silica sphere structures • Form: Natural elongated freeform specimen • Morphology: Angular tapered form with thicker basal section • Precious opal structure: Longitudinal ribbon like colour seam • Pattern: Ribbon / mosaic / shard like play of colour • Dominant colours: Electric Green, Neon Green, Aqua Blue and Vivid Blue • Secondary colours: Violet and subtle Lilac • Colour distribution: Concentrated primarily within an elongated internal seam • Body tone: Milky white to pale bluish translucent • Transparency: Translucent to semi translucent • Lustre: Vitreous • Matrix: Natural host material and earthy matrix traces present • Treatment: None • Condition: Natural specimen NOTABLE POINTS: • Exceptional Ribbon Like Colour Seam A concentrated band of precious opal runs longitudinally through the specimen and creates its defining visual structure. • Intense Electric Green Fire Bright green is the strongest colour response and repeatedly activates with exceptional luminosity under direct light. • Vivid Blue and Aqua Components Cool blue and aqua tones appear throughout the colour seam and contrast strongly with the brighter green flashes. • Violet and Lilac Secondary Flashes Subtle violet and lilac responses add further chromatic complexity between the dominant green and blue fields. • Mosaic and Shard Like Internal Pattern The colour seam is divided into irregular luminous cells and fragments that activate independently as the viewing angle changes. • Strong Multi Directional Play Of Colour The specimen does not depend on one fixed viewing position and reveals different colour zones through rotation. • Pale Translucent Opal Body The milky white to bluish body creates an excellent neutral background for the stronger chromatic seam. • Excellent Internal Contrast The intense green and blue colour fields remain sharply visible against the lighter surrounding opal. • Natural Boulder Opal Architecture Precious opal remains associated with traces of its original host material, preserving the geological identity of the specimen. • Distinctive Tapered Morphology Its elongated angular form and pointed extremity give the piece a recognisable natural silhouette. • Concentrated Colour Despite Compact Size The chromatic intensity of the central seam gives the specimen considerably more visual presence than its dimensions might suggest. • Classic Queensland Character The seam style formation is highly characteristic of Australian Boulder Opal from Queensland. COLLECTOR’S INTEREST: Australian Boulder Opal is especially valued when the relationship between precious opal and its natural host environment remains clearly visible. In this specimen, the principal collector feature is the elongated ribbon of precious opal that travels through the body rather than appearing as a small isolated colour patch. The concentration of electric green, vivid blue, aqua and violet within this narrow seam creates a particularly dynamic optical character. The internal mosaic and shard like structures divide the colour into multiple independent areas, allowing different sections to activate as the stone is moved. For collectors who appreciate natural opal formation rather than highly processed material, this specimen offers an especially attractive combination of vivid play of colour, seam architecture, natural morphology and Queensland provenance. LAPIDARY POTENTIAL: Selective cutting or polishing could theoretically expose or refine portions of the precious opal seam, but the present natural form already reveals the principal colour structure extremely well. Further intervention would reduce weight and could interrupt the continuous ribbon like architecture that gives the specimen its strongest identity. Its greatest collector value therefore lies in preservation as a natural Boulder Opal specimen, where the colour seam, surrounding opaline body and original geological character remain together. —————— Shipping and Handling: All orders are shipped by Portuguese National Post. • Dispatch time: within 1 to 3 business days after payment confirmation to Catawiki • Transit time with CTT service: between 5 to 7 business days within europe and worldwide, depending on destination national post. • A tracking number is always provided Photography and transparency: All photographs are taken under controlled lighting conditions using a macro lens, carefully selected to present each specimen as accurately as possible. No filters, colour enhancement, or artificial saturation are applied. The lighting setup uses a calibrated 5500K light source, replicating neutral daylight to reveal natural tones, surface features, and internal characteristics. Under warmer or weaker indoor lighting, colours may appear slightly different, which is normal. The purpose of this photographic process is documentation and representation, not visual enhancement. Images are intended to reflect the specimen faithfully as it appears under balanced natural light conditions. Identification and ethics: All specimens offered are natural and described to the best of our knowledge, based on direct sourcing, professional experience, and information provided by trusted suppliers working at the origin. Every effort is made to ensure transparency and accuracy regarding identification, locality, and general characteristics, avoiding misleading statements about treatment, provenance, or nature. Customs and import taxes: Any customs duties, import fees, or local taxes applied by the destination country are entirely the responsibility of the winning bidder. These charges are not included in the auction price or shipping cost and are determined by the buyer’s local authorities. Guarantee and resolution: Customer satisfaction is important. In the unlikely event of an issue such as loss, damage, or discrepancy, please contact us promptly through Catawiki’s messaging system. Each case is handled individually and fairly, with appropriate solutions offered when justified. Appreciation and commitment: We sincerely thank you for your trust. Our work focuses on careful selection, accurate representation, and respectful presentation of mineral specimens with character and interest. Each piece is chosen for its individual qualities rather than speculative or financial considerations. We aim to provide a transparent, reliable, and consistent experience for collectors at all levels. With gratitude, GemPulse Minerals