DESCRIPTION: Immediately commanding attention through its extraordinary colour intensity, this exceptional natural Dioptase crystal from the Mindouli District, Republic of the Congo, displays a deeply saturated emerald green to vivid bluish emerald green body, remarkable translucency and an exceptionally brilliant vitreous lustre. Rising as a dominant elongated crystal, the specimen culminates in a beautifully developed, sharply defined natural termination where the upper crystal faces converge into an elegant geometric apex. Viewed from different orientations, this termination reveals an impressive degree of crystallographic definition and symmetry, giving the crystal a powerful architectural presence while remaining entirely natural and unpolished. The main crystal presents an imposing elongated prismatic habit characteristic of well developed Dioptase, with broad faces that act almost like natural optical windows. Light penetrates extensively into the translucent body, revealing considerable internal depth and producing different concentrations of green as the crystal is rotated. The interaction between saturation and translucency is particularly attractive: thinner and clearer areas become intensely luminous, while greater crystal thickness concentrates the colour into deeper emerald tones. Across the natural faces, the strong vitreous lustre produces brilliant reflections that emphasise the geometry of the prism and the exceptional definition of the termination. Adding considerable mineralogical and aesthetic complexity, several secondary Dioptase crystals naturally emerge from the sides of the dominant prism. These attached crystals vary in orientation and development, creating a genuine three dimensional crystal association rather than an isolated single prism. Some project distinctly outward from the principal crystal while others remain integrated along its surface, producing multiple levels of relief. Their presence records successive natural crystallisation around the principal individual and gives the specimen a sculptural architecture that changes significantly according to the viewing angle. The extraordinary green colour is intrinsic to the mineral itself. Dioptase is a hydrated copper cyclosilicate with the chemical formula CuSiO₃·H₂O, and copper is responsible for its characteristic intense green to bluish green colouration. In this specimen, the combination of high chromatic saturation, substantial translucency and reflective crystal faces produces an especially vivid visual effect. Natural growth structures remain visible within and across the crystal, while the exceptionally glossy surfaces create flashes of light that contrast beautifully against the concentrated emerald body colour. The Mindouli District in the Pool Department of the Republic of the Congo is internationally recognised as one of the classic and most important localities for exceptional Dioptase. Material from this region is particularly celebrated for intense colour, strong crystal development and highly attractive vitreous lustre. At 13.85 carats and 22 mm in height, this specimen combines substantial presence with a dominant terminated prism, remarkable translucency, multiple associated crystals and extraordinary colour saturation, making it a highly expressive example of the mineralogical quality for which Congolese Dioptase has become internationally renowned. SPECIFICATIONS: • Weight: 2.77 g • Weight in carats: 13.85 ct • Dimensions: 22 × 12 × 10 mm • Origin: Mindouli District, Pool Department, Republic of the Congo • Mineral species: Dioptase • Chemical formula: CuSiO₃·H₂O • Mineral class: Cyclosilicate • Crystal system: Trigonal • Form: Natural dominant crystal with associated secondary crystals • Crystal habit: Elongated prismatic crystal with strongly developed terminal faces • Termination: Complete and sharply defined natural termination • Colour: Intense emerald green to vivid bluish emerald green • Colour saturation: Exceptionally strong and concentrated • Transparency: Translucent with highly translucent areas • Lustre: Strong vitreous lustre • Surface features: Natural crystal faces with visible growth structures • Associated crystallisation: Multiple naturally attached secondary Dioptase crystals • Internal features: Natural internal growth structures visible through translucent areas • Treatment: None • Condition: Natural, unpolished and untreated crystal NOTABLE POINTS: • Exceptional natural termination The dominant crystal culminates in a remarkably well defined geometric termination, with converging natural faces creating an elegant and highly expressive apex. • Extraordinary emerald colour saturation The crystal displays an exceptionally intense emerald green to bluish emerald green colour, immediately establishing the visual identity of the specimen. • Remarkable natural translucency Light penetrates deeply through extensive areas of the crystal, revealing internal depth while maintaining powerful colour concentration. • Powerful vitreous lustre The broad natural faces produce brilliant, almost mirror like reflections that strongly emphasise the geometry of the crystal. • Imposing elongated prismatic architecture The dominant vertical crystal creates a refined and immediately recognisable silhouette with excellent display presence. • Multiple secondary Dioptase crystals Several naturally associated crystals emerge from the sides of the principal prism, creating an intricate three dimensional crystallographic composition. • Strong variation under illumination Different crystal thicknesses produce transitions from luminous vivid green areas to deeper concentrated emerald zones. • Natural crystallographic complexity Growth structures, secondary crystallisation and geometric faces preserve an extensive visual record of the specimen’s natural formation. • Classic Mindouli provenance The specimen originates from one of the internationally recognised Congolese localities associated with highly saturated and beautifully crystallised Dioptase. • Exceptional combination of defining qualities Colour saturation, translucency, lustre, crystal architecture, secondary growth and a beautifully preserved termination are united within a single natural specimen. COLLECTOR’S INTEREST: Dioptase occupies a distinctive position among collector minerals because few species combine such extraordinary green saturation with transparent to translucent crystal development and brilliant vitreous lustre. Congolese material is especially appreciated internationally, and the Mindouli District belongs to the classic African localities associated with highly expressive Dioptase crystallisation. This specimen brings together the characteristics collectors seek most strongly in the species: intense emerald colour, a substantial 13.85 ct presence, an elongated dominant prism, remarkable translucency, brilliant natural faces, multiple associated crystals and, above all, an exceptionally well developed complete termination. The result is not simply an intensely coloured crystal, but a complete three dimensional mineralogical composition whose architecture remains visually compelling from multiple orientations. LAPIDARY POTENTIAL: Although translucent areas demonstrate the optical richness and gemological character of the material, this specimen is fundamentally a collector crystal rather than lapidary rough. Its dominant terminated prism, beautifully converging terminal faces, naturally associated secondary crystals, strong vitreous lustre and complete three dimensional crystallographic architecture constitute the defining qualities of the piece and are best appreciated in its present untouched state ——————- 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. 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