Search: 941 results found for "zeolite"

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

Statement Stilbite Specimen | 5.7KG | India

(0)

¥3,210.00

Moldavite Tektite - Intuitively Chosen Tektites 0.80 - 0.90 Grams Tali & Loz Crystals

Moldavite Tektite - Intuitively Chosen Tektites Less than 0.20 Grams Tali & Loz Crystals

Moldavite Tektite | Intuitively Chosen | Czech Republic

(2)

¥92.00

Indicolite Blue Tourmaline | Crystal | 45mm | Brazil

(0)

¥3,210.00

Raw Thulite 3cm, Sold as Seen

(0)

¥138.00

Zebradorite Sphere 5cm

(0)

¥175.00

Moldavite Tektite 4.85gr Tektites Tali & Loz Crystals

Moldavite Tektite | 4.85gr | Czech Republic

(0)

¥1,330.00

Malachite Stalactite 83gr , Zaire- Congo Minerals Tali & Loz Crystals

Malachite Stalactite | 83g | Zaire-Congo

(0)

¥441.00

Malachite Stalactite 115gr , Zaire- Congo Minerals Tali & Loz Crystals

Malachite Stalactite | 115g | Zaire-Congo

(0)

¥349.00

Angelite Tumblestones 20-30mm

(0)

¥42.00

Charoite Self Standing Slice 10cm, Russia Slices Tali & Loz Crystals

Charoite Self Standing Slice | Rough Edges | 10cm | Russia

(0)

¥899.00

Moldavite Tektite 5.76gr Tektites Tali & Loz Crystals

Moldavite Tektite | 5.76gr | Czech Republic

(0)

¥1,587.00

Watermelon Tourmaline and Cleavelandite in Smokey Quartz on Stand 13cm, Brazil Specimen Tali & Loz Crystals

Watermelon Tourmaline and Cleavelandite in Smokey Quartz | 13cm | Brazil

(0)

¥1,330.00

Selenite Spheres | Mini | 24mm | Morocco

(0)

¥46.00

Moldavite Tektite 4.73gr Museum Grade Tektites Tali & Loz Crystals

Moldavite Tektite | 4.73gr | Czech Republic

(0)

~~¥3,898.00~~ ¥1,949.00

Charoite Spheres | 2cm | Russia

(0)

¥184.00

Hyalite Opal Specimen, Hungary, 7x3.5cm

(0)

~~¥413.00~~ ¥207.00

Moldavite Tektite 8.42gr Museum Grade Tektites Tali & Loz Crystals

Moldavite Tektite | 8.42gr | Czech Republic

(0)

~~¥6,970.00~~ ¥3,485.00

Fishtail Selenite Specimen 363gr

(0)

¥1,284.00

Blog

Zeolite: Not One Mineral but a Family, and Why That Makes It Even More Interesting

What is Zeolite? Mineral Group: Tectosilicate | Category: Zeolite Group | Formula: Variable | Hardness: 3.5 – 5 (Mohs) Zeolite is not a single mineral but a family of related hydrated aluminosilicate minerals that share a distinctive open framework crystal structure and a common mode of formation in volcanic environments. The group includes dozens of recognised species, among them Stilbite, Heulandite, Scolecite, Analcime, Chabazite, Natrolite, and Thomsonite, each with its own specific chemistry, crystal habit, and physical properties, but all united by the same fundamental architectural principle: a three-dimensional lattice of silicon, aluminium, and oxygen that contains interconnected channels and cavities large enough to accommodate water molecules and exchangeable ions. The name Zeolite was coined in 1756 by the Swedish mineralogist Axel Fredrik Cronstedt, who observed that certain minerals frothed and appeared to boil when heated rapidly. He combined the Greek words zein, meaning to boil, and lithos, meaning stone, to produce the term. The boiling behaviour he observed results from the rapid expulsion of structural water trapped within the crystal framework as heat drives it out, a property that reflects the open, porous nature of the zeolite structure and remains one of the group's most characteristic features. Formation and Geological Context Zeolites form as secondary minerals, meaning they develop not during the primary crystallisation of a rock but through later chemical processes acting on existing volcanic material. The most common setting is within the cavities, vesicles, and fractures of basaltic and andesitic volcanic rocks, where silica-rich hydrothermal fluids circulate at relatively low temperatures, typically between 50 and 300 degrees Celsius. The process begins when volcanic rock, particularly basalt or volcanic ash and tuff, is buried and comes into contact with groundwater. The water dissolves silica, aluminium, and various cations from the surrounding rock and carries them in solution through the available void spaces. As these fluids cool, or as their chemistry changes through reaction with the host rock, the dissolved components begin to crystallise onto the cavity walls. Given sufficient time and stable conditions, well-formed crystals grow inward from the walls of the cavity, producing the characteristic drusy clusters that make Zeolite specimens so visually appealing. The temperature and pressure conditions of formation, along with the precise chemistry of the circulating fluid and the host rock, determine which specific Zeolite species crystallises. This is why different Zeolite species tend to be associated with different geological environments and depths within a volcanic sequence. Zeolites forming deeper in a sequence, where temperatures are higher, tend to differ systematically from those forming closer to the surface. Geologists use the distribution of Zeolite species through volcanic sequences as a tool for reconstructing the thermal history of the rock. Major producing regions include the Deccan Traps of India, one of the largest volcanic provinces on Earth, which has yielded some of the world's finest and most diverse Zeolite specimens. Iceland, where active and recently active volcanism provides ideal formation conditions, is another significant source. The western United States, parts of Eastern Europe, and various localities across Brazil and New Zealand also produce notable material. Indian Zeolite specimens are particularly celebrated among collectors for the scale and quality of their crystal formations, frequently occurring in large basalt cavities alongside Apophyllite, Calcite, and Chalcedony in combinations that are among the most visually spectacular in mineralogy. Key Physical Properties Property Detail Mineral Group Tectosilicate Category Zeolite Group Crystal System Variable by species Hardness 3.5 – 5 Mohs Specific Gravity 2.0 – 2.4 (variable) Refractive Index Variable by species Lustre Vitreous to pearly Fracture Uneven Cleavage Perfect to good depending on species Tenacity Brittle Transparency Transparent to translucent Colour Colourless, white, cream, peach, pink, green Formula Variable (hydrated aluminosilicates) Safe to Cleanse in Water Brief contact tolerated; prolonged soaking not recommended The variable physical properties across the group reflect the structural and chemical diversity of the individual species. Specific gravity tends to be low across all Zeolites relative to other silicate minerals, a direct consequence of the open framework structure that contains significant void space within the crystal lattice. This porosity, which is what makes Zeolites so scientifically and industrially significant, also makes them less dense than most minerals of comparable chemistry. The Open Framework Structure The defining characteristic of all Zeolites, the feature that unifies the group and explains both their geological behaviour and their industrial importance, is the open framework structure. Understanding it helps make sense of almost everything else about these minerals. In most silicate minerals, silicon and oxygen atoms form compact, densely packed arrangements that leave little internal space. In Zeolites, the silicon and oxygen framework is built around a three-dimensional network of interconnected rings and channels, creating a structure that is more like a microscopic sponge or a molecular cage than a solid lattice. Aluminium substitutes for silicon at various points in the framework, and the resulting charge imbalance is compensated by cations such as sodium, potassium, calcium, or magnesium occupying positions within the channels. Water molecules also occupy these channels, held loosely within the structure by electrostatic attraction rather than by strong chemical bonds. This is why Zeolites can be dehydrated by heating without the crystal structure collapsing, and why they can reabsorb water from the surrounding environment when cooled. The channels are large enough for water molecules and small ions to pass through freely, which is the basis for the ion exchange and molecular sieving properties that make Zeolites so valuable industrially. The specific geometry of the channels varies between species and determines which molecules or ions can enter and which cannot, essentially acting as a molecular size filter. This precise selectivity is what makes different Zeolite species useful for different industrial applications, from water softening to catalytic cracking in petroleum refining. Principal Collector Species While the Zeolite group contains over 40 naturally occurring species, a handful account for the vast majority of collector specimens and are worth knowing individually. Stilbite is one of the most widely collected Zeolites, recognised by its characteristic sheaf-like or bow-tie crystal aggregates. It typically occurs in white, cream, peach, or pale salmon tones and forms some of the most elegant natural crystal arrangements available to collectors. Fine Stilbite specimens from the Deccan Traps of India are benchmarks of the group. Heulandite forms flattened, coffin-shaped crystals, a habit distinctive enough to make identification straightforward even without chemical analysis. It occurs in a range of colours including colourless, white, yellow, orange, and green, the latter coloured by trace amounts of nickel. Large transparent Heulandite crystals from Iceland are among the finest in the group. Scolecite forms slender, acicular crystals that often grow in radiating or divergent sprays. It is typically colourless to white and has a particularly silky lustre on crystal surfaces. Scolecite from Nashik in India has produced some of the most spectacular radiating crystal clusters known from the group. Analcime forms well-developed trapezohedron crystals, a form with 24 triangular faces that gives it a rounded, almost spherical appearance. It is typically colourless to white and is one of the more common Zeolites in basaltic rocks worldwide. Natrolite forms needle-like prismatic crystals with a characteristic square cross-section and perfectly smooth faces. It is typically colourless to white with a bright vitreous lustre and is found in many of the same basaltic localities as other Zeolite species. Zeolites in Industry and Science The industrial significance of Zeolites extends far beyond their importance to mineral collectors and is worth understanding as context for what makes the group structurally unusual. Natural Zeolites have been used for centuries in construction materials, water purification, and agriculture. Synthetic Zeolites, engineered to have specific channel geometries and chemical properties, are now produced in vast quantities and are among the most commercially important materials in modern chemistry. The global synthetic Zeolite market is measured in millions of tonnes annually. In petroleum refining, Zeolites serve as catalysts in the fluid catalytic cracking process that converts heavy crude oil fractions into more useful lighter products including petrol. In detergents, they replace phosphates as water softeners by exchanging calcium and magnesium ions for sodium. In gas separation and purification, their molecular sieving properties allow specific molecules to be selectively absorbed or excluded. In medicine, Zeolites are being investigated for drug delivery, wound treatment, and dialysis applications. The natural specimens in a mineral collection are a window into the same structural principles that underpin all of these applications, formed not in a chemical plant but over thousands of years within a basalt cavity. Mineral Associations One of the features that makes Zeolite specimens particularly appealing to collectors is the richness of their mineral associations. Because they form as part of a broader secondary mineralisation event within volcanic cavities, Zeolites are frequently found alongside other minerals that crystallised from the same hydrothermal fluids under similar conditions. Apophyllite is perhaps the most celebrated associate, and the combination of Apophyllite and Stilbite or Scolecite on a single basalt matrix piece from India represents one of the most recognisable and sought after combinations in the collector market. Calcite occurs widely alongside Zeolites in many localities. Chalcedony, a fine-grained silica mineral, often lines cavity walls as a precursor to Zeolite formation or fills remaining void space. Prehnite, Pectolite, and various other secondary silicates are also common associates depending on locality. Care and Handling Zeolites contain structural water as part of their crystal framework and are consequently sensitive to conditions that affect their hydration state. Rapid heating or exposure to very dry environments can cause dehydration stress, potentially resulting in surface dulling, micro-fracturing, or in extreme cases structural damage. Brief contact with water is generally tolerated by most Zeolite species, but prolonged soaking is not recommended. The combination of relatively low hardness (ranging from 3.5 to 5 on the Mohs scale) and brittle tenacity means that Zeolite crystals, particularly the fine acicular habits of species like Natrolite and Scolecite, are vulnerable to mechanical damage. Handle specimens with care and support the matrix rather than gripping individual crystals. Store in stable indoor conditions away from heat sources, direct sunlight, and significant humidity fluctuations. Clean with a soft dry brush. Avoid ultrasonic cleaning equipment, which can shatter delicate crystal aggregates, and any liquid-based cleaning methods that involve prolonged contact. Traditional Associations While this guide focuses on the science of Zeolites, individual species within the group are valued in spiritual and mindful practices for a range of associations connected to their specific colours, habits, and energies. These associations are rooted in cultural and traditional use rather than scientific properties. For explorations of individual Zeolite species in spiritual practice, see our dedicated guides to Stilbite and Scolecite. Summary Zeolite is one of the most structurally distinctive and scientifically significant mineral groups available to collectors. Formed through low temperature hydrothermal processes within volcanic cavities, the individual species that make up the group offer a remarkable diversity of crystal habits, colours, and associations within a shared architectural framework. The same open channel structure that makes natural Zeolite specimens so visually compelling is the basis for one of the most industrially important classes of materials in modern chemistry. Whether encountered as a delicate spray of Scolecite needles, a peach-toned Stilbite sheaf, or a glassy Heulandite crystal, every Zeolite specimen is a record of slow, patient crystallisation from hydrothermal fluids within ancient volcanic rock. Shop all Zeolite 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 Stilbite: The Zeolite That Looks Like a Bow Tie Scolecite: The Silky Zeolite From the Heart of a Volcano Apophyllite: The Glassy Mineral That Grows Alongside Zeolites Clear Quartz: The Mineral Inside Your Watch, Your Phone, and Your Collection Black Tourmaline: The Mineral That Generates Its Own Electricity Everything you Need to Know about Quality Of Crystals Zeolite Family Mineral Guides

on Apr 16 2025

Blog

Stilbite: The Mineral That Grew in a Bubble and Came Out Wearing a Bow-Tie

What is Stilbite? Mineral Group: Silicate, Zeolite Group | Category: Tectosilicate | Formula: NaCa₄[Al₉Si₂₇O₇₂]·30H₂O | Hardness: 3.5 – 4 (Mohs) Stilbite is a hydrated sodium calcium aluminosilicate mineral belonging to the zeolite group, one of the most well-known and widely collected members of that large and scientifically significant mineral family. It is recognised by its characteristic sheaf-like or bow-tie crystal aggregates, its soft peach to salmon coloration, and the warm, almost glowing quality of its finest specimens. The name derives from the Greek stilbein, meaning to glitter or shine, a reference to the pearly lustre on the cleavage surfaces of the mineral that catches light in a way quite different from the sharper, more vitreous lustre of harder minerals. Stilbite was first formally described in 1797 from Indian material, and India remains one of the most celebrated sources of fine specimens today. The Deccan Traps basalt province of Maharashtra, which has yielded some of the finest zeolite specimens in the world, is particularly associated with Stilbite and the extraordinary combination specimens in which it grows alongside Apophyllite, Heulandite, and other zeolite group minerals on basalt matrix. For a full explanation of how zeolites form, what the zeolite group is, and why these minerals are scientifically and industrially significant, see our dedicated Zeolite Mineral Guide. This guide focuses on the specific properties, formation, and character of Stilbite within that broader family. Formation and Geological Context To understand how Stilbite forms, it helps to picture what happens inside a piece of volcanic rock over thousands to millions of years. When lava flows cool and solidify, they trap bubbles of gas within the rock as they harden. These bubbles, called vesicles, leave small void spaces scattered through the solidified basalt. Over geological time, groundwater percolates slowly through the rock, dissolving silica, aluminium, calcium, and sodium from the surrounding minerals as it moves. As this mineral-rich water works its way into the void spaces and begins to cool, the dissolved minerals start to crystallise onto the cavity walls. Stilbite is one of the minerals that grows from this process. The specific combination of calcium, sodium, aluminium, silica, and water available in the fluid, combined with the relatively low temperatures of this secondary crystallisation process, produces the Stilbite structure. The crystals grow inward from the cavity walls, often developing the characteristic sheaf or bow-tie habit as multiple crystal blades grow from a central point and splay outward. The water that is an integral part of Stilbite’s formula, indicated by the ·30H₂O component, is held within the open channel structure of the zeolite framework rather than simply coating the surface. This structural water is part of what makes Stilbite and all zeolites behave differently from most minerals when heated: rather than simply melting, they release their structural water as steam, which is why the original zeolite name means boiling stone in Greek. The most celebrated source of fine Stilbite specimens is the Deccan Traps basalt of Maharashtra in India, particularly localities around Pune and Nashik, which have produced sheaf and bow-tie specimens of exceptional size, colour quality, and crystal perfection. Iceland produces fine material from its active and recently active volcanic geology. Scotland, the Faroe Islands, Nova Scotia in Canada, and various localities in the United States are other significant sources. Key Physical Properties Property Detail Mineral Group Silicate, Zeolite Group Category Tectosilicate Crystal System Monoclinic Hardness 3.5 – 4 Mohs Specific Gravity 2.12 – 2.22 Refractive Index 1.478 – 1.496 Birefringence 0.018 – 0.022 Pleochroism None Lustre Pearly to vitreous Fracture Uneven to splintery Cleavage Perfect in one direction Tenacity Brittle Colour Peach, salmon, orange, white, colourless Streak White Formula NaCa₄[Al₉Si₂₇O₇₂]·30H₂O Safe to Cleanse in Water No The specific gravity of 2.12 to 2.22 is notably low, lower even than Quartz at 2.65, reflecting the open porous structure of the zeolite framework with its large internal channels and relatively light sodium and calcium components. The low refractive index of 1.478 to 1.496 produces the characteristic pearly rather than vitreous quality of the lustre, and the perfect cleavage in one direction explains why split surfaces show that soft, almost silky sheen that is so characteristic of Stilbite specimens. The Sheaf and Bow-Tie Habit One of the most immediately recognisable features of Stilbite is its crystal habit, the characteristic shape in which individual crystals develop and aggregate. Understanding how and why this habit forms adds geological depth to what might otherwise seem a purely aesthetic observation. Stilbite crystals are individually tabular or platy, meaning each crystal is relatively flat in one dimension and broader in the other two. When multiple tabular crystals grow outward from a central point with their flat faces roughly parallel and their edges fanning outward, they create the characteristic sheaf shape: a cluster that resembles a bundle of wheat stalks tied at the centre and splaying out at both ends. When the sheaf is seen end-on, the overlapping fan of crystal edges produces a shape that resembles a bow-tie or an hourglass. Both descriptors, sheaf and bow-tie, describe the same fundamental growth pattern viewed from different angles. Some particularly well-developed specimens show multiple sheaves intergrown at different orientations, creating complex, architecturally intricate clusters. This growth habit is a direct expression of the monoclinic crystal symmetry of Stilbite and the way the dominant crystal faces develop most rapidly during growth from the hydrothermal fluid. The specific geometry is characteristic enough that an experienced collector can identify Stilbite from its habit alone before examining any other physical property. The Peach Colour: What Produces It The warm peach to salmon orange colour that is most associated with Stilbite is not present in all specimens: pure Stilbite is actually colourless to white, and the peach and orange tones are produced by trace impurities incorporated during crystallisation. The colouration in peach and orange Stilbite is primarily attributed to trace amounts of iron oxide, most likely Hematite or Goethite in finely dispersed form, incorporated into the crystal structure or present as microscopic inclusions during growth. These iron oxide impurities absorb blue wavelengths and reflect warm orange and yellow tones, producing the characteristic peach colour that has become so closely associated with Stilbite in the collector market. The depth of colour varies considerably between specimens and localities. The finest deep salmon-orange material from certain Indian localities is particularly valued. White and colourless Stilbite represents material that crystallised from fluids with minimal iron content. Pale blush tones are intermediate. The specific colour of any given specimen reflects the iron chemistry of the particular hydrothermal fluid that was present in that specific cavity at the time of crystallisation. It is worth noting that the colour can fade in some specimens over extended periods of sustained exposure to strong sunlight, as the iron oxide colour centres can be affected by prolonged UV exposure. Displaying Stilbite away from direct sustained sunlight preserves the peach colour quality over the long term. Stilbite and Its Companions: The Indian Matrix Combination No discussion of Stilbite would be complete without acknowledging the Indian combination specimens that have made it one of the most celebrated display minerals in the collector world. In the basalt cavities of the Deccan Traps, Stilbite frequently grows alongside other zeolite group minerals, most notably Apophyllite, Heulandite, and Scolecite, as well as with Calcite and Chalcedony. The combination of peach Stilbite sheaves with the transparent to translucent cubic or pyramidal crystals of green or colourless Apophyllite on dark basalt matrix is considered one of the most visually spectacular naturally occurring mineral combinations available to collectors. These combination specimens form because multiple mineral species can crystallise simultaneously or sequentially from the same hydrothermal fluid in the same cavity, each taking advantage of the specific chemical and physical conditions that favour its own crystallisation. The fact that Apophyllite and Stilbite so frequently grow together reflects their shared formation environment and the specific fluid chemistry of the Deccan Traps basalt system, which provides the right balance of silica, calcium, fluorine, potassium, sodium, and aluminium to produce both minerals together. For a collector interested in the zeolite group and the secondary mineralisation of basalt, a fine Indian Stilbite and Apophyllite combination specimen represents one of the most complete and visually accessible illustrations of this geological process available. Stilbite Within the Zeolite Family Stilbite is one of the most collected zeolite species but sits within a much larger family of structurally related minerals. Understanding where it fits helps contextualise its specific properties and distinguishes it from other zeolites sometimes encountered in collections. All zeolites share the same fundamental open framework aluminosilicate structure with large internal channels that can accommodate water molecules and exchangeable cations. What differs between species is the precise geometry of the framework, the specific cations present, and the resulting crystal habits and properties. For a full exploration of the zeolite group and its principal collector species, see our Zeolite Mineral Guide. Stilbite is closely related to Heulandite, and the two minerals share such similar chemistry and crystal structure that they were for many years considered varieties of the same species. Modern mineralogy separates them based on the dominant cation: Stilbite has sodium as the dominant large cation alongside calcium, while Heulandite is calcium-dominant. The visual difference in hand specimens is subtle, and the two are frequently found growing together in the same cavities. Care and Handling Stilbite requires careful handling because of its moderate hardness, perfect cleavage, structural water content, and sensitivity to moisture. At hardness 3.5 to 4 it scratches relatively easily and should be stored away from all harder minerals with generous soft padding. The perfect cleavage in one direction means that stress applied perpendicular to the cleavage plane can cause clean splitting, and the splintery fracture means broken surfaces can be sharp. Handle specimens by supporting the full matrix base rather than gripping individual crystal clusters. Water should be avoided entirely. Despite the water in its structure, Stilbite should not be cleansed with water: the delicate crystal surfaces can be affected by liquid water contact, and sustained moisture can work into the cleavage and grain boundaries of the crystal aggregates over time. Clean with a soft dry brush applied very gently, and store in a stable, dry environment away from humidity fluctuation. The colour can fade under sustained strong UV light exposure over extended periods, so display away from direct sunlight as a long-term preservation measure. Traditional Associations While this guide focuses on the mineralogy and science of Stilbite, it is valued in spiritual and mindful practices for its associations with love, compassion, calm, and gentle healing. Its warm peach colour and soft lustre have linked it naturally to the Heart Chakra, Third Eye, and Crown Chakras in crystal traditions, and it is widely used in practices focused on emotional healing, dream work, and the cultivation of loving awareness. These associations are rooted in cultural and traditional use rather than scientific properties. For a full exploration of how to work with Stilbite spiritually, see our dedicated spiritual guide. Summary Stilbite is a hydrated sodium calcium aluminosilicate zeolite whose characteristic sheaf and bow-tie crystal habit, warm peach to salmon coloration, and pearly lustre make it one of the most visually elegant members of the zeolite family. Forming in the vesicles and cavities of basaltic volcanic rocks through the slow crystallisation of mineral-rich hydrothermal fluids, it is most celebrated in its Indian form, where it grows alongside Apophyllite and other zeolites in combination specimens that represent some of the most visually extraordinary natural mineral arrangements available to collectors. Handle it gently, keep it dry, and display it away from sustained direct light, and it will retain the warm, glowing character that has made it a consistently valued presence in mineral collections since its first formal description over two centuries ago. Browse our full Stilbite collection to find Indian matrix specimens, sheaf clusters, and combination pieces with Apophyllite. 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 Zeolite: Not One Mineral but a Family, and Why That Makes It Even More Interesting Amethyst: Mineral Guide at Tali & Loz Selenite: The Stone of Higher Consciousness Pyrite: Harness the Power of Confidence and Manifestation Grape Agate: Named After Fruit, Not Quite an Agate, Entirely Fascinating

on Feb 02 2025

Search results

Search results

Search results

Search results

VIP Club members receive 10% off