Search: 649 results found for "white calcite"

Grey & White Calcite with Stilbite | Display Specimen | 200mm | China Minerals Tali & Loz Crystals

Grey & White Calcite with Stibnite | Display Specimen | 200mm | China

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£110.00

Silver on Calcite Specimen 27.90gr, Sold as Seen

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£140.00

Silver on Calcite Specimen, Sold as Seen Specimen Tali & Loz Crystals

Silver on Calcite Specimen 5cm, Sold as Seen

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£170.00

Cobaltoan Calcite with Malachite | DRC

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£51.00

Caribbean Calcite Hearts | 3cm | Pakistan

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£5.00

Honey Calcite Specimen 8cm | Mexico

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~~£55.00~~ £35.00

Dogtooth Calcite Specimen 178gr

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~~£48.00~~ £24.00

Statement Stilbite Specimen 5.7KG, Sold As Seen Minerals Tali & Loz Crystals

Statement Stilbite Specimen | 5.7KG | India

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£350.00

Optical Rose Pink Calcite Block 5.5cm

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~~£42.00~~ £21.00

White Quartz Towers | 8.5–8.7cm | India

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£12.00

Dogtooth Calcite Specimen, 24cm

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£230.00

Sphalerite | 95mm | Picos de Europa, Santander, Spain

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£175.00

Calcite Tubular Cluster | 41.33g | China

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£65.00

Mangano Calcite Heart | Small | Intuitively Chosen

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£5.00

Okenite Specimen | 13.5cm | India

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£48.00

Crystals for Intuition

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£10.00

Thulite Palmstone 5.5cm | Sold As Seen

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£38.00

Calcite On Dolomite Specimen 10.5cm Specimen Tali & Loz Crystals

Calcite On Dolomite Specimen 10.5cm, Missouri, USA

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£85.00

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Zebra Calcite: Every Stripe a Chapter of Geological History

What is Zebra Calcite? Mineral Group: Carbonate | Category: Calcite | Formula: CaCO₃ | Hardness: 3 (Mohs) Zebra Calcite is a banded variety of Calcite from Mexico, characterised by alternating black and white or dark grey and cream bands that create the striking striped appearance its name describes. It belongs to the same mineral species as Blue Calcite, Cobaltoan Calcite, and the countless other Calcite colour varieties: all are calcium carbonate, CaCO₃, distinguished from one another by the trace elements and impurities that produce their different colours rather than by any difference in their fundamental chemistry. Calcite itself is one of the most abundant minerals on Earth. It is the principal component of limestone, marble, and chalk, and it forms in a remarkable range of geological environments from the shells of marine organisms to cave stalactites to hydrothermal veins. What makes Zebra Calcite distinctive within this large and varied family is the specific combination of dark carbon or organic-rich bands alternating with pale, purer calcite bands, creating a natural striped pattern that is both visually dramatic and geologically interesting. The material comes primarily from Mexico, where it is found in sedimentary sequences and has become a significant commercial source for the collector and decorative stone market. The specific geological conditions of the Mexican deposits produce the pronounced, regular banding that makes the finest specimens so visually striking. Formation and Geological Context To understand how Zebra Calcite forms, it helps to think about how Calcite forms generally first. Calcite precipitates from calcium carbonate-rich water: when water carrying dissolved calcium and carbonate minerals loses carbon dioxide, either through evaporation, temperature change, or biological activity, the dissolved minerals come out of solution and crystallise as Calcite. This process happens everywhere from the sea floor, where marine organisms build shells and skeletons from Calcite, to cave systems, where dripping groundwater deposits stalactites and stalagmites, to sedimentary basins, where Calcite accumulates layer by layer over millions of years. Zebra Calcite forms in a sedimentary environment where the chemistry of the depositing water changed periodically over time. The white or cream bands represent periods when relatively pure calcium carbonate was depositing, with minimal organic material or other impurities in the water. The dark bands, typically black to dark grey, represent periods when organic material, carbon-rich sediment, or other dark mineral impurities were present in higher concentrations alongside the carbonate, becoming incorporated into the calcite as it crystallised. Think of it like reading a natural diary: each pair of light and dark bands records one cycle of changing conditions in the depositional environment. Wider bands suggest longer periods of stable conditions; narrower bands suggest more rapid changes. The regularity of the banding in the finest Zebra Calcite specimens reflects a depositional environment where conditions alternated in a relatively consistent pattern over geological time. The dark colouration of the black bands is primarily attributed to organic carbon content, the same type of organic material that colours black limestone and dark shale in sedimentary sequences worldwide. Some specimens also contain traces of Aragonite, the calcium carbonate polymorph, alongside the dominant Calcite. Key Physical Properties Property Detail Mineral Group Carbonate Category Calcite Crystal System Trigonal Hardness 3 Mohs Specific Gravity 2.71 Refractive Index 1.486 – 1.658 Birefringence 0.172 Pleochroism None Lustre Vitreous to resinous Fracture Conchoidal to uneven Cleavage Perfect in three directions Tenacity Brittle Colour Black and white banded Streak White Formula CaCO₃ Safe to Cleanse in Water No The birefringence value of 0.172 is one of the highest of any common mineral and is worth highlighting because it produces a visible optical effect in transparent Calcite: place a clear piece of Calcite over text and you will see two images rather than one, as the crystal splits light into two rays travelling at different speeds. This dramatic double refraction is not visible in Zebra Calcite because the banding and opacity of the material prevent clear light transmission, but it is the same fundamental optical property of the Calcite crystal structure that has made transparent Iceland Spar Calcite historically important in the development of optical science. The perfect cleavage in three directions means that Zebra Calcite, like all Calcite varieties, can split cleanly along flat planes if struck at the right angle. Despite the moderate hardness of 3, this cleavage means it requires more careful handling than the hardness number alone suggests. What Makes the Stripes: The Chemistry of the Banding The banding in Zebra Calcite is one of the most immediately visually striking features of the material, and understanding what produces each colour zone adds a layer of geological meaning to what might otherwise seem a purely decorative pattern. The white to cream bands represent relatively pure calcium carbonate deposited during periods when the water carrying the dissolved minerals was clean and low in organic matter. Calcium carbonate in its pure form is white to colourless, and these pale bands are the baseline Calcite without significant impurity. The black to dark grey bands represent intervals when the depositional environment changed. Organic material, the decomposed remains of biological organisms, carbon-rich sediment, or both were present in the water during these periods and became incorporated into the crystallising Calcite. Organic carbon is black, and even small amounts distributed through the Calcite matrix are enough to produce the deep dark tones that contrast so dramatically with the pale bands. This same banding mechanism, alternating periods of clean carbonate deposition and organic-rich deposition, produces the dark layers in many black and grey limestones worldwide. Zebra Calcite is simply a particularly well-developed and visually dramatic expression of a very common sedimentary geological process. Each stripe is a chapter in the environmental history of the Mexican basin where the material formed. Zebra Calcite Within the Calcite Family Calcite is one of the most colour-diverse mineral species known, producing an extraordinary range of appearances from the same fundamental calcium carbonate chemistry. Understanding where Zebra Calcite sits within this family helps contextualise what makes it distinctive. The colour diversity of Calcite arises from trace element substitutions and impurities. Cobaltoan Calcite is vivid pink from cobalt. Blue Calcite is pale blue from fine silicate inclusions. Mangano Calcite is pink from manganese. Orange Calcite gets its warm tones from iron oxide. Caribbean Calcite combines pale blue Calcite with brown Aragonite. Yellow Calcite derives its colour from iron. For a closer look at two of the most popular colour varieties, our guides to Blue Calcite and Orange Calcite explore how the same fundamental mineral produces such different energetic and visual characters. Zebra Calcite occupies its own distinctive space within this family because its defining characteristic is not a single trace element producing a uniform colour but the regular alternation of two very different zones: one essentially pure and one organic-rich. This makes it more of a sedimentary record than a colour variety in the usual sense, and the pattern itself is as geologically informative as any chemical impurity. Care and Handling Zebra Calcite requires careful handling for the same reasons as all Calcite varieties: low hardness, perfect cleavage in three directions, and sensitivity to water and acids. At hardness 3, Zebra Calcite scratches easily and will be marked by most everyday surfaces and materials. Store separately from all harder minerals with generous soft padding. Avoid placing on abrasive surfaces and handle with clean, dry hands. Water should be avoided. Calcite is slightly soluble in water, particularly acidic water, and prolonged contact will dull and etch polished surfaces over time. Even brief contact followed by incomplete drying can begin to affect surface quality on fine specimens. Clean with a soft dry cloth only. If gentle cleaning is needed, a barely damp cloth applied very briefly followed by immediate thorough drying is the maximum recommended. The perfect cleavage in three directions means that a sharp knock in the wrong direction can split the specimen cleanly regardless of its overall hardness. Handle with care, support the full base of specimens rather than gripping edges, and store in padded, stable mounts. Traditional Associations While this guide focuses on the science of Zebra Calcite, it is valued in spiritual and mindful practices for its associations with balance, empowerment, and harmony across all energy centres. Its black and white banding has led to associations with the integration of opposites, the balance of light and shadow, and the grounding of higher awareness into practical everyday life. These associations are rooted in cultural and traditional use rather than scientific properties. For a full exploration of how to work with Zebra Calcite spiritually, see our dedicated spiritual guide. Summary Zebra Calcite is a banded Calcite from Mexico whose striking black and white stripes record alternating periods of clean carbonate deposition and organic-rich sedimentation in an ancient depositional environment. Each pair of bands is a geological chapter, and the regularity of the banding in the finest specimens reflects a depositional environment whose conditions cycled with unusual consistency over geological time. Within the extraordinarily diverse Calcite family it occupies a distinctive position: not defined by a single trace element colour but by the visual record of changing environmental chemistry preserved in sedimentary layers. Durable enough for display and collection but soft enough to require careful handling, it is one of the more visually dramatic members of the carbonate mineral group. Browse our full Zebra Calcite collection to find polished slabs, towers, spheres, and raw specimens. As always, our inbox and DMs are open if you would like guidance or simply wish to explore further. Contact us Love, Laura Further Reading Cobaltoan Calcite: The Vivid Pink of the Calcite Family Mangano Calcite: Gentle Pink Energy and Heart Healing Caribbean Calcite: Ocean Blues and Earthy Browns Aragonite: Earth Star and Grounding Energy Pyrite: Harness the Power of Confidence and Manifestation

on Jan 29 2025

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Yellow Calcite: The Sunshine in a Family That Produces Every Colour in the Spectrum

What is Yellow Calcite? Mineral Group: Carbonate | Category: Calcite | Formula: CaCO₃ | Hardness: 3 (Mohs) Yellow Calcite is a colour variety of Calcite, the calcium carbonate mineral that is one of the most abundant on Earth, distinguished by warm yellow to golden tones produced by iron impurities within the crystal structure. It belongs to the same mineral species as Blue Calcite, Cobaltoan Calcite, Zebra Calcite, and the many other Calcite colour varieties: all are fundamentally the same calcium carbonate mineral, with colour differences arising entirely from trace elements and impurities rather than from any change in the essential chemistry. Calcite forms the primary component of limestone, marble, and chalk, and it is produced in vast quantities by marine organisms that use dissolved calcium carbonate from seawater to build their shells and skeletons. When these organisms die and their remains accumulate on the sea floor over millions of years, they build the sedimentary sequences that eventually become limestone, and it is within these sequences and the hydrothermal veins that cut through them that most collector-quality Calcite varieties, including Yellow Calcite, are found. The name Calcite derives from the Latin calx, meaning lime, a reference to the quicklime produced when limestone is heated, one of the oldest and most significant chemical processes in human technological history. Yellow Calcite inherits this name and this history while adding the specific character of its iron-driven colour. Formation and Geological Context Yellow Calcite forms in sedimentary and hydrothermal environments through the same fundamental process as all Calcite varieties: the precipitation of calcium carbonate from mineral-rich water. The process is straightforward to understand. Water dissolves calcium and carbonate ions from surrounding rocks as it percolates through the ground. When conditions change, whether through evaporation, temperature shifts, or changes in pressure and carbon dioxide content, these dissolved ions come out of solution and crystallise as Calcite. This happens in cave systems where dripping water builds stalactites, in sedimentary basins where layer after layer of carbonate accumulates, and in hydrothermal veins where hot mineral-rich fluids cool and deposit their mineral load. The yellow colour enters the picture through iron. The rocks through which the calcium-carbonate-bearing water moves often contain iron-bearing minerals. Small amounts of iron, specifically in the Fe³⁺ oxidation state, are dissolved into the water alongside the calcium and carbonate and become incorporated into the Calcite structure as it crystallises. This iron, even in very small concentrations, absorbs blue wavelengths of visible light and reflects yellow and orange, producing the warm golden tones that define Yellow Calcite. The depth of yellow in any given specimen depends on how much iron was incorporated during crystallisation. Pale, almost cream-coloured material contains very little iron. Deep golden yellow material contains more. This variation between specimens from the same locality, and between different localities worldwide, reflects the natural variation in iron availability in different geological environments. Major sources of Yellow Calcite include Mexico, which produces some of the finest commercial material, as well as the United States, Peru, Brazil, and various localities across Europe and Asia. Mexico in particular has a rich tradition of producing high-quality Calcite specimens of many colour varieties, and yellow material from Mexican sedimentary and hydrothermal deposits is among the most widely available in the collector market. Key Physical Properties Property Detail Mineral Group Carbonate Category Calcite Crystal System Trigonal Hardness 3 Mohs Specific Gravity 2.71 Refractive Index 1.486 – 1.658 Birefringence 0.172 Pleochroism None Lustre Vitreous to resinous Fracture Conchoidal to uneven Cleavage Perfect in three directions Tenacity Brittle Colour Pale yellow to deep golden yellow Streak White Formula CaCO₃ Fluorescence Sometimes present under UV Safe to Cleanse in Water Quick rinse only The birefringence value of 0.172 deserves a mention because it is one of the highest of any common mineral and produces a visible optical effect worth experiencing firsthand. Place a clear piece of Calcite over a printed word and you will see the word doubled: the crystal splits light into two rays travelling at slightly different speeds, producing two separate images. This effect, called double refraction, is not visible in most Yellow Calcite because the yellow colour and typical opacity of the material prevent clear light transmission, but it is a property of every Calcite crystal regardless of colour. The perfect cleavage in three directions means Calcite will split cleanly along flat planes if knocked at the right angle, producing rhombohedron-shaped fragments. This is a defining diagnostic property of Calcite and one of the most immediately recognisable features of any broken specimen. The Yellow Colour: Iron in the Calcite Structure Most coloured minerals get their colour from a trace element that substitutes into the crystal structure and absorbs specific wavelengths of light. In Yellow Calcite, iron in the Fe³⁺ oxidation state is the primary colouring agent. Iron is one of the most common elements in the Earth's crust, and it turns up as a trace impurity in a vast number of minerals. In Calcite's calcium carbonate structure, small amounts of iron can substitute for calcium within the crystal lattice during formation. When Fe³⁺ iron occupies these sites, it absorbs light in the blue and violet parts of the visible spectrum. The wavelengths left over after this absorption are the yellows and oranges that reach the eye. This is the same fundamental mechanism that colours many other yellow and orange minerals: Citrine gets its yellow from a different iron configuration in Quartz, Hessonite Garnet gets its warm orange from iron-bearing inclusions, and Topaz can show yellow tones from iron impurities. In each case iron is the common thread, but the specific structural environment in which the iron sits determines the exact shade of colour produced. It is also worth noting that Yellow Calcite can sometimes be confused with Yellow Fluorite or with light honey-coloured Amber in polished form. The streak test is the quickest distinction: Calcite always leaves a white streak, while Amber leaves a pale yellowish streak and is not a mineral at all. The specific gravity of 2.71 for Calcite is also reliable: Amber is dramatically lighter at around 1.05, and Fluorite at 3.18 is heavier. Fluorescence in Yellow Calcite Yellow Calcite sometimes displays fluorescence under ultraviolet light, emitting a visible glow when a UV lamp is shone on it. This property varies between specimens and is not present in all Yellow Calcite, but where it occurs it adds an additional layer of scientific interest. Fluorescence in Calcite is typically produced by manganese impurities in the Mn²⁺ oxidation state, which absorb UV energy and re-emit it as orange to yellow visible light. The colour of the fluorescence can therefore differ from the body colour of the specimen: a Yellow Calcite piece might show orange fluorescence under UV because the manganese activator produces a different emission colour from the iron that produces the yellow body colour. Testing Yellow Calcite under both shortwave and longwave UV is a simple and rewarding exercise: different specimens from different localities respond differently, and the variation in fluorescent response reflects the variation in trace element chemistry between geological sources. Some pieces will glow brightly, others not at all, and the difference tells you something about the specific impurity suite of each specimen. Yellow Calcite Within the Calcite Family Calcite is one of the most colour-diverse mineral species known, and Yellow Calcite is just one of many visually distinct varieties produced by different trace element combinations within the same fundamental calcium carbonate structure. Blue Calcite gets its pale blue tones from fine silicate inclusions or trace impurities that scatter blue light. Cobaltoan Calcite is vivid pink from cobalt substituting for calcium. Mangano Calcite is pink from manganese. Orange Calcite, closely related to Yellow Calcite, contains higher iron concentrations that push the colour from yellow into orange and red-orange territory. Zebra Calcite displays alternating black and white bands from organic carbon impurities. Caribbean Calcite combines pale blue Calcite with brown Aragonite. Green Calcite gets its colour from chlorite inclusions. Yellow Calcite occupies the warm, sunny end of this family, its iron-driven colour placing it alongside the oranges and golds rather than the cooler blues and pinks. Within the family it is one of the more widely available and accessible varieties, appearing in many geological settings worldwide wherever iron-bearing water has deposited calcium carbonate. Care and Handling Yellow Calcite requires careful handling for the same reasons as all Calcite varieties: low hardness, perfect cleavage in three directions, and moderate sensitivity to water and acids. At hardness 3, Yellow Calcite scratches easily and should be stored separately from all harder minerals with soft padding. A copper coin at hardness 3.5 will scratch it, and most other minerals in a collection will do so even more readily. Avoid placing on abrasive surfaces and handle with clean, dry hands. Water contact should be limited to a quick, gentle rinse if needed, followed by immediate and thorough drying. Calcite is slightly soluble in water and prolonged contact, particularly with acidic water, will dull and etch polished surfaces over time. The best everyday cleaning method is a soft dry cloth. The perfect cleavage in three directions means that a sharp impact at the right angle can split even a solid-looking piece cleanly. Handle with care and avoid knocking against hard surfaces. Traditional Associations While this guide focuses on the science of Yellow Calcite, it is valued in spiritual and mindful practices for its associations with confidence, inner strength, mental clarity, and solar energy. Its warm yellow colour has linked it naturally to the Solar Plexus Chakra across crystal traditions, and it is commonly used in practices focused on motivation, personal empowerment, and clarity of thought. These associations are rooted in cultural and traditional use rather than scientific properties. For a full exploration of how to work with Yellow Calcite spiritually, see our dedicated spiritual guide. Summary Yellow Calcite is an iron-coloured variety of one of the Earth's most abundant and geologically significant minerals. Its warm yellow to golden tones arise from Fe³⁺ iron substituting into the calcium carbonate crystal structure during formation, a colour mechanism shared with many other yellow and orange minerals but producing in Calcite a distinctively warm, sometimes translucent quality that reflects the specific optical properties of the trigonal carbonate structure. Within the extraordinarily diverse Calcite family it occupies the warm, energetic end of the colour spectrum, available in many geological settings worldwide and accessible at every level of collecting. Handle it with respect for its softness and cleavage, keep it dry, and it will reward you with a quietly radiant presence in any collection. Browse our full Yellow Calcite collection to find raw specimens, towers, spheres, and polished pieces. As always, our inbox and DMs are open if you would like guidance or simply wish to explore further. Contact us Love, Laura Further Reading Cobaltoan Calcite: The Vivid Pink of the Calcite Family Mangano Calcite: Gentle Pink Energy and Heart Healing Caribbean Calcite: Ocean Blues and Earthy Browns Aragonite: Earth Star and Grounding Energy Pyrite: Harness the Power of Confidence and Manifestation

on Jan 30 2025

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