Search: 85 results found for "blue sapphire"

Blue Topaz Tumblestones 10-20mm

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71,00 kr

Tanzanite Gem 1.65gr, Tanzania Gem Tali & Loz Crystals

Tanzanite Gem | 1.65g | Tanzania

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579,00 kr

Blue Lace Agate Palmstones | 4/5.5cm | India

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270,00 kr

Blue Baryte Crystal Cluster Specimen 14.3cm | Sold as Seen

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8.353,00 kr

Blue Tigers Eye Sphere | Small 18-22mm

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84,00 kr

Blue Kyanite Tower | India | Intuitively Chosen

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206,00 kr

Blue Quartz Tower | 93mm | Brazil

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116,00 kr

Labradorite Hearts | Large 3.5x3cm | Madagascar

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65,00 kr

Indicolite Blue Tourmaline | Crystal | 45mm | Brazil

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4.498,00 kr

Twin Tanzanite Gem 60gr, Tanzania Gem Tali & Loz Crystals

Twin Tanzanite Gem | 60g | Tanzania

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8.353,00 kr

Lapis Lazuli Spheres | 20mm | Afghanistan

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123,00 kr

Aquamarine Tumblestones | 15-25mm | Brazil

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65,00 kr

Aquamarine Specimen 15.7gr, Sold as Seen Specimen Tali & Loz Crystals

Aquamarine Specimen | 15.7gr | Pakistan

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2.056,00 kr

Blue Apatite | 143g | India

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322,00 kr

Shattuckite Specimen | 217g | Kaokoveld Plateau, Namibia

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707,00 kr

Lapis Lazuli Cabochon | 1.1cm | Afghanistan

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193,00 kr

Blue Lace Agate Tumblestones | South Africa Tumblestones Tali & Loz Crystals

Blue Lace Agate Tumblestones | 20-40mm | Namibia

(0)

65,00 kr

Lapis Lazuli Egg | 0.6kg | Madani, Afghanistan

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1.221,00 kr

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Aquamarine: The Iron Chemistry Behind the Sea-Blue Beryl

What is Aquamarine? Mineral Group: Silicate | Category: Beryl Variety | Formula: Be₃Al₂Si₆O₁₈ | Hardness: 7.5 – 8 (Mohs) Aquamarine is the pale blue to blue-green gem variety of Beryl, a beryllium aluminium cyclosilicate mineral and one of the most important gemstone species in mineralogy. Its name derives directly from the Latin aqua marina, meaning water of the sea, a reference to the pale, translucent blue that defines the variety at its finest and that has made it one of the most enduringly valued gemstones across cultures and centuries. The colour ranges from near-colourless with a hint of blue through pale sky blue to deeper blue and blue-green, with the most prized material showing a rich, saturated blue with minimal green component. Beryl as a mineral species produces more named gem varieties than almost any other single species in mineralogy. Emerald is the green chromium and vanadium-bearing variety. Morganite is the pink manganese-bearing variety. Heliodor is the yellow iron-bearing variety. Red Beryl, also known as Bixbite, is an extremely rare manganese-coloured variety found almost exclusively in Utah. Golden Beryl is the pure yellow variety. All of these, along with colourless Goshenite, are the same mineral species with different trace element colorations. Aquamarine sits within this family as the iron-coloured blue variety, its colour produced specifically by iron in the Fe²⁺ oxidation state within the hexagonal beryl structure. Browse our Aquamarine collection to find rough crystals, cut stones, and matrix specimens. Formation and Geological Context Aquamarine forms primarily in granitic pegmatites, the exceptionally coarse-grained, volatile-rich igneous rocks that crystallise from the final stages of granitic magma. Pegmatites concentrate the rare elements that do not easily fit into common rock-forming minerals, including beryllium, which is an essential component of Beryl and is present in the Earth’s crust at very low average concentrations of roughly 2 to 6 parts per million. The concentration of beryllium into pegmatitic melts through the process of magmatic differentiation is the fundamental geological prerequisite for Beryl crystallisation, which is why gem-quality Beryl of all varieties is associated almost exclusively with pegmatite environments. Within the pegmatite, Aquamarine crystallises as the melt cools and volatile elements including water, fluorine, and beryllium become concentrated in the residual fluid. The iron that produces the blue colour is incorporated from the surrounding geological environment into the growing crystal structure, with Fe²⁺ ions substituting into the structural channels of the Beryl framework. The specific oxidation state of the iron is critical: Fe²⁺ produces blue, while Fe³⁺ produces yellow, and the presence of both simultaneously produces a green colour. Heat treatment, which converts Fe³⁺ to Fe²⁺ by reducing the iron, is the standard practice used to remove unwanted yellow and green components from natural Aquamarine and is widely accepted in the gem trade. Aquamarine also occurs in metamorphic rocks derived from beryllium-rich igneous protoliths, and in alluvial deposits where weathering has liberated crystals from their host pegmatites and concentrated them in stream sediments. Another exceptional gem that forms in the pegmatite and high-temperature metamorphic environment is Tanzanite, though its geological story is quite different — found in a single locality in Tanzania and potentially running out within a generation. The most significant sources of gem-quality Aquamarine include Minas Gerais in Brazil, which has produced some of the largest and finest crystals ever recorded, including the Dom Pedro Aquamarine, the largest cut Aquamarine gemstone in existence at 10,363 carats, now in the Smithsonian Institution. Other major sources include Pakistan, particularly the Shigar Valley in the Karakoram Mountains, which produces exceptionally fine deeply coloured material, Nigeria, Madagascar, Mozambique, and various localities in Russia, the United States, and China. Key Physical Properties Property Detail Mineral Group Silicate Category Beryl Variety Crystal System Hexagonal Hardness 7.5 – 8 Mohs Specific Gravity 2.65 – 2.85 Refractive Index 1.567 – 1.590 Birefringence 0.005 – 0.009 Pleochroism Weak to distinct: blue and colourless to pale blue Lustre Vitreous Fracture Conchoidal to uneven Cleavage Indistinct Tenacity Brittle Colour Pale blue to blue-green Streak White Formula Be₃Al₂Si₆O₁₈ Safe to Cleanse in Water Yes The hardness of 7.5 to 8 combined with indistinct cleavage makes Aquamarine one of the more durable gemstones available, better suited to everyday jewellery wear than many softer or more cleavage-prone stones. The hexagonal crystal system produces the characteristic long prismatic crystals with a hexagonal cross-section that make Aquamarine one of the most recognisable rough gemstone crystals. The pleochroism, showing blue along one axis and near-colourless to pale blue along another, is taken into account by gem cutters when orienting the stone for maximum colour face-up. The Beryl Structure and the Role of Iron The colour mechanism in Aquamarine is one of the better-studied in gemology and worth understanding in some detail because it explains both the colour and the standard heat treatment applied to most commercial material. Beryl has a cyclosilicate structure in which six-membered rings of silicon-oxygen tetrahedra are stacked in columns, creating channels running through the crystal along the hexagonal axis. These channels are large enough to accommodate water molecules, alkali metal ions, and other species, and their presence contributes to the chemical complexity and colour variety of the Beryl family. Iron ions can occupy two different structural sites within the Beryl framework: the tetrahedral sites normally occupied by silicon, and the octahedral sites normally occupied by aluminium, and the colour produced differs depending on which site the iron occupies and in what oxidation state. Fe²⁺ in the structural channels produces the blue of Aquamarine through an intervalence charge transfer process between adjacent iron ions. Fe³⁺ substituting into the aluminium octahedral sites produces yellow. When both are present simultaneously the blue and yellow combine to produce the green colour seen in unheated material from many localities. Heating Aquamarine to approximately 400 to 450 degrees Celsius converts the Fe³⁺ to Fe²⁺ through a reduction reaction, removing the yellow component and leaving only the blue, producing the purer, more commercially desirable blue colour. This treatment is stable, permanent, and universally accepted in the gem trade. Understanding this chemistry explains why Aquamarine from some localities, where the iron is predominantly already in the Fe²⁺ state, is naturally blue without treatment, while material from other localities requires heating to achieve the same colour. It also explains why overheating can bleach the colour entirely by driving out the iron-bearing species from the structural channels. Aquamarine Within the Beryl Family The Beryl family is one of the most colour-diverse in gemology, and placing Aquamarine within it provides important context for both its chemistry and its value. Emerald is the green chromium and vanadium-bearing variety and is the most commercially valuable member of the family, with fine Colombian Emerald commanding prices that exceed those of comparable Ruby and Sapphire. The inclusion-rich nature of most natural Emerald, a consequence of the hydrothermal formation conditions that produce the finest colour, means that the trade applies a different clarity standard to Emerald than to other gemstones, accepting inclusions described as the jardin, or garden, of the stone as characteristic rather than as defects. Morganite is the pink to peach manganese-coloured variety, found notably in Brazil, Madagascar, and Afghanistan, and has grown significantly in commercial popularity in recent decades as a rose gold jewellery stone. Its colour can overlap with the pink-orange of Imperial Topaz and with pink Tourmaline in the commercial market. Heliodor is the yellow iron-bearing variety, its colour produced by Fe³⁺ rather than the Fe²⁺ of Aquamarine, which is the chemical inverse of the heat treatment relationship discussed above. Red Beryl from the Wah Wah Mountains of Utah is among the rarest gemstones known, with fine specimens commanding prices comparable to the finest Emerald. Goshenite, the colourless variety, is the purest form and was historically used as a lens and mirror material before optical glass became widely available. All Beryl varieties share the same fundamental hexagonal structure and the same hardness, specific gravity range, and optical properties. The colour differences arise entirely from different trace element substitutions within the same crystal framework, making Beryl one of the clearest illustrations in mineralogy of how a single mineral species can produce the full visual spectrum through trace element chemistry. Aquamarine in History The human relationship with Aquamarine reaches back to classical antiquity and has remained continuous through to the present day, making it one of the more historically well-documented gemstones. Ancient Greek and Roman texts describe Aquamarine and attribute to it connections to the sea and to the god Neptune. Sailors in the ancient Mediterranean carried Aquamarine as a talisman for safe passage, a tradition that persisted through the medieval period and into the age of exploration. The physical resemblance of the pale blue stone to clear seawater made the association immediate and intuitive across multiple cultures independently. In the Roman world, Aquamarine was used in carved intaglios, as a lens for optical purposes in early spectacles, and as a component of elaborate jewellery. Pliny the Elder describes it in his Natural History, noting its connection to the sea and its value as a gemstone. Medieval European lapidaries consistently list Aquamarine among the significant gemstones and attribute various protective and communicative properties to it. The discovery of the major Brazilian deposits in the eighteenth and nineteenth centuries dramatically increased global supply and established Brazil’s position as the world’s leading Aquamarine producer, a position it retains today. The largest Aquamarine crystal ever found, the Minas Gerais crystal from which the Dom Pedro gemstone was cut, weighed approximately 110 kilograms before faceting, a scale that gives some sense of the extraordinary crystal growth possible in the Brazilian pegmatite environment. Care and Handling Aquamarine is among the more robust gemstones available for both collection and jewellery use. Its hardness of 7.5 to 8 provides excellent resistance to everyday scratching, and the indistinct cleavage means it does not split preferentially under impact in the way that more cleavage-prone stones such as Topaz do. These properties make it well suited to rings, bracelets, and other high-wear jewellery settings with reasonable care. Water cleansing is safe. Aquamarine has no soluble components and does not react with water under normal conditions. Clean with mild soapy water, rinse thoroughly, and dry completely. Ultrasonic cleaning is generally safe for clean, inclusion-free material but should be avoided for heavily included specimens where vibration could propagate through existing fractures. The primary long-term care consideration is light and heat exposure. The iron-based colour of Aquamarine is generally stable under normal conditions, but sustained intense UV exposure or heat above several hundred degrees can affect the colour over very long periods. Under normal wearing and display conditions this is not a practical concern, but prolonged display in direct strong sunlight over many years should be avoided for the finest coloured material. Traditional Associations While this guide focuses on the mineralogy and science of Aquamarine, it carries one of the most consistent and cross-cultural sets of traditional associations of any gemstone, connected almost universally to the sea, to calm, to communication, and to protection in travel. In chakra work it is associated with the Throat Chakra. These associations are rooted in deep cultural tradition rather than scientific properties. For a full exploration of how to work with Aquamarine spiritually, see our dedicated spiritual guide. Summary Aquamarine is the iron-coloured blue variety of Beryl, a beryllium cyclosilicate formed in granitic pegmatites where the rare element beryllium becomes concentrated through magmatic differentiation. Its colour, produced by Fe²⁺ ions within the hexagonal channel structure of the crystal, is stable, often heat-treated to remove unwanted green or yellow components, and among the most consistently valued pale blues in the gemstone world. From ancient Mediterranean sailors to the record-breaking Dom Pedro Aquamarine in the Smithsonian, it has maintained a continuous presence in human culture for over two thousand years. Durable, water-safe, and available in a range of qualities from accessible tumbled material to exceptional gem crystals, it is one of the most rewarding members of the Beryl family to collect and understand. Browse our full Aquamarine collection to find rough crystals, cut stones, and matrix 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 Blue Kyanite: One Mineral, Two Hardnesses, and a Billion Year Story Labradorite: The Stone the Inuit Called Frozen Aurora Rubellite Tourmaline: The Pink-Red Gem of the Tourmaline Family Chrysoprase: The Nickel-Coloured Chalcedony A Beginner’s Guide to Mineral Physical Properties A Beginner’s Guide to Mineral Optical Properties

on Mar 23 2025

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Blue Kyanite: One Mineral, Two Hardnesses, and a Billion Year Story

What is Blue Kyanite? Mineral Group: Nesosilicate | Category: Kyanite | Formula: Al₂SiO₅ | Hardness: 4.5 – 7 (Mohs) Blue Kyanite is an aluminium silicate mineral, meaning it is built from a combination of aluminium, silicon, and oxygen atoms bonded together into a stable crystalline structure. It forms deep within the Earth under conditions of intense pressure during mountain-building events, and it is this high pressure origin that gives Kyanite many of its most distinctive physical characteristics. Its name comes from the Greek word kyanos, meaning deep blue, and it is easy to see why: the finest specimens display a rich, saturated blue that ranges from pale ice-blue through to deep sapphire, often within a single crystal. What makes Blue Kyanite immediately interesting, even to collectors just starting out, is something you can test yourself. Kyanite has two different hardness values depending on which direction you scratch it. Along the length of the crystal it is relatively soft, around 4.5 on the Mohs scale. Scratch it across the width and it jumps to around 6.5 to 7. This directional variation in hardness, known as anisotropic hardness, is unusual in the mineral world and makes Kyanite a reliable conversation piece in any collection. Kyanite belongs to a group of three minerals that share exactly the same chemical formula — Al₂SiO₅ — but form under completely different geological conditions. These three minerals are Kyanite, Andalusite, and Sillimanite. Think of them as three versions of the same recipe that turn out differently depending on the heat and pressure of the oven. Kyanite is the high pressure version. Finding it in a rock tells geologists something very specific about the depth and tectonic conditions that rock has been through. Formation and Geological Context Blue Kyanite forms through a process called regional metamorphism. Metamorphism simply means the transformation of existing rock under heat and pressure without the rock ever melting. Regional metamorphism happens on a large scale during events like continental collisions, when vast bodies of rock are pushed deep into the Earth’s crust. The weight of the rock above creates enormous pressure, and the heat from deep within the Earth adds to that. Over millions of years, the original minerals in the rock break down and recrystallise into new, more stable forms. Kyanite is one of those new forms. It grows as elongated, bladed crystals, often described as looking like flat paddles or the blade of a knife. These crystals frequently display colour zoning, where the core of the crystal is a deeper, richer blue and the outer edges fade to paler or near-colourless material. This happens because the trace elements responsible for the blue colour, primarily iron and titanium, were more concentrated in the surrounding fluid at the beginning of crystal growth and gradually became depleted as the crystal grew outward. Blue Kyanite is found in significant quantities in Nepal and Brazil, which are the main sources of gem-quality material. Other notable locations include the Alps in Switzerland and Austria, parts of the eastern United States along the Appalachian mountain range, Russia, and Kenya. The pattern is worth noticing: almost every major Kyanite locality is associated with ancient or active mountain belts. That is not a coincidence. Mountains are where the deep, high pressure rocks get pushed back up to the surface and exposed by millions of years of erosion, bringing Kyanite with them. Key Physical Properties Property Detail Mineral Group Nesosilicate Category Kyanite Crystal System Triclinic Hardness 4.5 (parallel) – 7 (perpendicular) Mohs Specific Gravity 3.53 – 3.65 Refractive Index 1.710 – 1.734 Birefringence 0.018 – 0.030 Pleochroism Weak to none Lustre Vitreous to pearly on cleavage faces Fracture Splintery, fibrous Cleavage Perfect in two directions Tenacity Brittle Colour Blue, green, black, white, grey Formula Al₂SiO₅ Safe to Cleanse in Water Yes Specific gravity is a measure of how dense a mineral is compared to water. Kyanite’s specific gravity of 3.53 to 3.65 is notably high for a silicate mineral, roughly three and a half times denser than water, and reflects the tight atomic packing that results from its high pressure formation. The triclinic crystal system simply means Kyanite crystals have the lowest possible internal symmetry of any crystal structure, with no planes of symmetry at all, which contributes to the asymmetric, bladed shape that makes individual crystals so visually striking. Colour and Appearance Pure aluminium silicate is colourless. The blue in Blue Kyanite comes entirely from trace amounts of iron and titanium that substitute into the crystal structure during formation. The more of these elements present, and the more evenly distributed they are, the richer and more saturated the blue. This is why colour quality varies so significantly from specimen to specimen and from locality to locality — it depends entirely on the chemistry of the geological environment where each crystal grew. Kyanite also occurs in a range of colours beyond blue. Black Kyanite contains abundant graphite or other opaque inclusions within its structure. Green Kyanite, coloured by chromium rather than iron, is found primarily in Tanzania and Kenya and is highly regarded by collectors. Orange Kyanite, a rarer variety found in Tanzania, gets its colour from manganese. White and grey specimens are also known. You can also find beautiful Ruby in Kyanite specimens, where deep red Ruby crystals grow directly within the Kyanite matrix — a striking combination of two high pressure metamorphic minerals. One subtle detail worth looking for in any Kyanite specimen is the difference in lustre across different surfaces. Surfaces that run along the natural cleavage planes have a soft, almost silky pearly sheen. Surfaces cutting across the crystal at other angles catch the light more sharply with a brighter, glassy vitreous lustre. This variation is a direct result of how the atomic structure is arranged in different directions through the crystal. Kyanite and Its Polymorphs To fully appreciate Blue Kyanite it helps to understand its relationship to Andalusite and Sillimanite. All three minerals are made of exactly the same elements in exactly the same proportions, but their atoms are arranged differently inside the crystal structure. Minerals that share a chemical formula but have different internal arrangements are called polymorphs. The three Al₂SiO₅ polymorphs each form under a specific window of pressure and temperature conditions. Andalusite forms at relatively low pressure and low to moderate temperature, typically in rocks that have been heated by a nearby magma body rather than buried deeply. Sillimanite forms at high temperature, in the deepest and hottest parts of metamorphic terranes. Kyanite occupies the high pressure field, forming where burial is deep and tectonic compression is intense. Because geologists have mapped out these stability fields precisely, identifying which of the three polymorphs is present in a rock sample allows them to reconstruct the pressure and temperature conditions that rock experienced, sometimes hundreds of millions of years ago. For experienced collectors, owning specimens of all three is a way of holding three different chapters of geological history in one hand. Industrial Uses Blue Kyanite is not only a collector mineral. It has significant industrial applications that most people are unaware of. When heated to temperatures above around 1,100 degrees Celsius, Kyanite permanently converts to a material called Mullite, a highly heat-resistant aluminium silicate, along with a small amount of glassy silica. During this conversion the material expands in volume by roughly 16 to 18 percent. This predictable, permanent expansion is extremely useful in industrial manufacturing. By incorporating Kyanite into ceramic mixtures, manufacturers can engineer precise dimensional changes during firing. This makes Kyanite a key raw material in refractory products: kiln furniture, furnace linings, spark plugs, and other components that must withstand extreme heat without cracking or deforming. Global industrial production of Kyanite runs to hundreds of thousands of tonnes each year, a scale that dwarfs the gem and collector market many times over. Care and Handling Despite its hardness across the crystal, Blue Kyanite has perfect cleavage in two directions, meaning it will split cleanly and easily along those planes if struck or stressed in the wrong direction. Bladed crystals are particularly vulnerable at their tips and along thin edges. Handle specimens with steady support rather than gripping them at one end, and avoid dropping or knocking them against hard surfaces. Blue Kyanite is safe to cleanse in water and has no components that will dissolve or degrade under normal conditions. There is no need for prolonged soaking however, and specimens with existing cracks or fractures should be dried thoroughly afterwards to prevent any moisture working into the structure over time. Store with soft padding between pieces to protect delicate crystal edges, and avoid ultrasonic cleaning for any cut gemstones, as the vibration can propagate along cleavage planes and cause fracture. Traditional Associations While this guide focuses on the science of Blue Kyanite, it is widely appreciated in spiritual and mindful practices for its associations with communication, clarity, and inner alignment. These associations are rooted in cultural and traditional use rather than scientific properties. For a full exploration of how to work with Blue Kyanite spiritually, see our dedicated spiritual guide. Summary Blue Kyanite is a high pressure metamorphic mineral with a geological story written into every crystal. Its anisotropic hardness, perfect cleavage, and striking blue coloration make it one of the more scientifically distinctive minerals a collector can own, while its relationship to Andalusite and Sillimanite gives it a broader significance as a record of deep crustal conditions. Whether you are drawn to it for its appearance, its geology, or both, it is a mineral that offers something new every time you look more closely. Shop all Blue Kyanite 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 Unlocking the Transformative Power of Crystals for Teens The Best Crystals for Extroverts & How to Use Them Black Tourmaline: Unveil Your Shield of Strength and Purification Charoite: A Journey of Transformation and Spiritual Growth Top 15 Crystals and Stones for Healers Herkimer Diamonds: Discover Clarity and Spiritual Illumination Selenite: The Stone of Higher Consciousness Angelite: How Vanished Oceans Produced a Pale Blue Mineral Agate: Mineral Profile, Formation, and Banding Explained

on Jan 21 2025

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