DESCRIPTION: This natural rough diamond presents a highly distinctive triangular morphology, combining well defined crystallographic geometry with pronounced surface textures, visible growth striations and naturally developed trigons. The interplay between form, crystallographic detail and metallic grey lustre creates a diamond of strong mineralogical and aesthetic interest. The triangular morphology is the defining feature of this crystal, yet it is far from rigid or planar. Each edge flows subtly into the next, with rounded transitions that soften the geometry without erasing its angular identity. The result is a rare balance between geometric clarity and natural evolution, where the crystal appears both structured and organic at the same time. Its colour displays a refined grey tone with metallic undertones, shifting between soft silver and deeper graphite depending on the angle of observation. This chromatic neutrality enhances the perception of form, allowing light interaction and surface structure to take visual priority over colour saturation. The surface reveals pronounced growth striations, particularly visible along the triangular faces, where linear textures run with clear directional consistency. These natural markings act as a record of crystallisation, adding both visual rhythm and geological authenticity to the crystal. One of the most remarkable features of this diamond is the presence of naturally developed trigons visible on the crystal faces. Trigons are triangular etch features formed through natural dissolution processes that occur during the geological evolution of a diamond. These structures are among the most sought after crystallographic features found on rough diamonds because they provide direct evidence of the crystal's natural history and are widely regarded as geological fingerprints preserved on the surface of the stone. Light interaction is especially compelling. Rather than relying on transparency, the diamond expresses itself through reflection and scattering. The adamantine lustre is present across multiple micro planes, producing sharp flashes that contrast with darker internal zones. Under stronger illumination, the crystal develops a subtle internal glow, reinforcing its metallic character without losing depth. The lower portion of the crystal displays slightly softer tonalities than the upper faces, creating subtle visual variation and enhancing the perception of depth. This relationship between the more defined triangular faces and the gentler lower zones contributes to the overall harmony of the crystal. Recovered from the alluvial deposits of Lunda Norte, Angola, this crystal remains completely natural, unpolished and untreated. It preserves a rare morphological expression where triangular geometry, natural surface preservation, growth structures and well developed trigons coexist in a highly desirable crystallographic combination. This is not simply a grey diamond. It is a natural crystal where geometry, texture, crystallographic detail and light converge into a singular expression of diamond formation. SPECIFICATIONS • Weight: 0.13 g • Weight in carats: 0.65 ct • Dimensions: 5 × 5 × 3 mm • Origin: Lunda Norte, Angola • Gem material: Natural diamond • Crystal form: Natural rough crystal • Morphology: Triangular crystal with rounded transitions • Colour: Grey with metallic undertones • Colour distribution: Even with subtle tonal variation • Transparency: Translucent to semi opaque • Lustre: Adamantine with reflective intensity • Surface features: Pronounced growth striations, trigons and micro crystalline textures • Trigons: Naturally developed triangular etch features • Condition: Natural, unpolished, untreated NOTABLE POINTS: • Distinct triangular crystal morphology Well defined geometry creates an immediately recognisable and highly aesthetic crystal habit. • Naturally preserved trigons Displays clearly visible triangular etch features highly sought after by collectors of rough diamonds. • Strong crystallographic interest Trigons provide direct evidence of natural dissolution processes during the diamond's geological evolution. • Metallic grey colour expression Displays refined grey tones with silver and graphite nuances that shift depending on lighting conditions. • Pronounced growth striations Clearly visible directional textures enhance both visual structure and geological authenticity. • High quality adamantine lustre Multiple reflective planes produce sharp, bright flashes across the crystal surface. • Light driven visual behaviour The crystal responds dynamically to illumination, with reflections dominating over transmission. • Subtle internal tonal variation Natural changes in tone enhance depth and visual complexity. • Fully natural untreated crystal No cutting, polishing or artificial enhancement. • Angolan alluvial origin Consistent with diamond material known for exceptional natural surface preservation. • Rare combination of morphology and trigons The coexistence of a triangular habit and visible trigons significantly enhances collector desirability. • Preserved geological history Surface structures remain intact, allowing direct observation of natural crystallographic processes. • Strong mineralogical character A crystal appreciated not only for aesthetics but also for its geological significance. • Excellent macro photography response Surface textures, lustre and trigons become particularly expressive under magnification. COLLECTOR’S INTEREST: Diamonds that deviate from classic octahedral or cubic expressions hold particular interest among collectors, especially when the morphology remains recognisable and structurally complete. This crystal offers precisely that rarity. Its triangular geometry is not superficial but integral to its formation. The combination of metallic grey tones, pronounced surface textures, visible growth structures and preserved trigons creates a crystal that appeals equally to aesthetic collectors and those interested in crystallography. The presence of trigons further elevates collector interest. These triangular surface features are among the most respected and desirable crystallographic characteristics found on rough diamonds because they provide visible evidence of the natural geological processes that shaped the crystal over immense periods of time. Collectors actively seek diamonds displaying well preserved trigons due to both their rarity and their scientific significance. The coexistence of a triangular crystal habit and visible trigons creates a particularly attractive combination, bringing together two highly desirable crystallographic characteristics within a single natural diamond. It is a crystal that communicates structure before colour and geological history before brilliance. LAPIDARY POTENTIAL: While the material could theoretically be cut, doing so would permanently remove the very features that define the identity of the crystal. The triangular morphology, natural growth striations and especially the preserved trigons would all be lost through any form of faceting or reshaping. These surface characteristics represent a significant portion of the crystal's collector value and geological interest. In its current form, the diamond holds substantially greater value as a natural crystal. It represents a rare example where crystallographic geometry, surface history and geological authenticity remain fully preserved. The preservation of the trigons alone provides a compelling argument for maintaining the crystal in its natural state, where both its aesthetic appeal and scientific significance can be fully appreciated. ——————- Shipping and Handling: All orders are shipped by Portuguese National Post and UPS • Dispatch time: within 1 to 3 business days after payment confirmation to Catawiki • Transit time service: between 2 to 5 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