Search: 68 results found for "black tourmaline"

Acicular Black Tourmaline Specimen 9.85gr

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~~£50.00~~ £25.00

Acicular Black Tourmaline Specimen 14.20gr

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Acicular Black Tourmaline Specimen 10.15gr

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~~£50.00~~ £25.00

Acicular Black Tourmaline Specimen 17.45gr

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~~£50.00~~ £25.00

Acicular Black Tourmaline Specimen 15.35gr

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~~£50.00~~ £25.00

AAA - Grade Acicular Tourmaline 15g

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~~£50.00~~ £25.00

Tourmaline in Quartz Tumblestones 20-30mm

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~~£6.50~~ £4.00

Multicolour Tourmaline From Quebec, Canada Specimen Tali & Loz Crystals

Multicolour Tourmaline From Quebec 271gr, Canada

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£345.00

Blue-Green Bi-Colour Tourmaline | 10.25g | Brazil

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£75.00

Dravite Brown Tourmaline | Raw | 35.7g

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£75.00

Dravite Brown Tourmaline | Raw | 17.72g

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£35.00

Confidence Crystal Gift Set

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£10.00

Dravite Brown Tourmaline | Raw Crystal | 17.50g

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£35.00

Beginner Crystal set

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£12.00

Dalmatian Jasper Tumblestones 20-30mm

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£4.00

Rubellite Tourmaline Crystal | 35mm | Brazil

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£110.00

Verdelite Green Tourmaline | Crystal | 33mm | Brazil

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£50.00

Tourmaline in Clear Quartz Cluster 371gr

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£120.00

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Black Tourmaline: The Mineral That Generates Its Own Electricity

What Is Black Tourmaline? Mineral Group: Tourmaline | Category: Cyclosilicate | Formula: NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄ | Hardness: 7 – 7.5 (Mohs) Black Tourmaline, known mineralogically as Schorl, is the most common member of the tourmaline group and one of the most widely distributed black minerals in the world. It belongs to the cyclosilicate category, a class of silicate minerals characterised by silicon-oxygen tetrahedra arranged in closed rings. Schorl's distinctive black colouration and complex chemistry set it apart from other tourmaline varieties, making it a favourite among collectors and a well-studied mineral in geological research. The name Schorl predates formal mineralogy, recorded in use before the 1400s in reference to a village in Saxony, Germany, near which significant deposits were found. It was not until the 18th century that tourmaline was recognised as a distinct mineral species, with Schorl later confirmed as its iron-dominant end member. How Does It Form? Black Tourmaline most commonly forms through hydrothermal processes within igneous and metamorphic environments. It is a characteristic mineral of granite pegmatites, exceptionally coarse-grained igneous rocks that form during the late stages of magma crystallisation when residual fluids are highly enriched in water, boron, and a range of trace elements. As these mineral-rich fluids cool and move through fractures in the surrounding rock, boron, sodium, aluminium, iron, and silicon combine to crystallise into the complex trigonal structure characteristic of all tourmaline group minerals. It is the elevated iron content during this crystallisation process that produces Schorl's deep, opaque black colour. Black Tourmaline also occurs in metamorphic rocks such as schists and gneisses, where it develops during the recrystallisation of pre-existing boron-bearing minerals under heat and pressure. Notable sources include Brazil, which produces some of the world's finest Schorl specimens, as well as Sri Lanka, Pakistan, the United States, Namibia, and Madagascar. Key Physical Properties at a Glance Property Detail Chemical Formula NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄ Crystal System Trigonal Hardness 7 – 7.5 (Mohs) Specific Gravity 3.06 – 3.25 Refractive Index 1.624 – 1.644 Birefringence 0.018 – 0.040 Pleochroism Weak to none Lustre Vitreous to resinous Fracture Uneven to conchoidal Cleavage None Special Properties Pyroelectric and piezoelectric Safe to Cleanse in Water Yes (brief only) Black Tourmaline's specific gravity ranges between 3.06 and 3.25, noticeably denser than Quartz at 2.65, which reflects its higher iron content. Its refractive index of 1.624 to 1.644 produces a vitreous to resinous lustre. Birefringence ranges from 0.018 to 0.040, higher than Quartz, though this is rarely visible to the naked eye in an opaque mineral. Pleochroism is weak to absent, consistent with its opacity. Piezoelectricity and Pyroelectricity Two of Black Tourmaline's most scientifically interesting properties are its piezoelectricity and pyroelectricity. Piezoelectricity refers to the ability of a mineral to generate an electric charge in response to applied mechanical pressure. When Schorl crystals are compressed or stressed, their asymmetric crystal structure causes a measurable electrical polarisation across the crystal. Pyroelectricity is the related ability to generate an electric charge in response to changes in temperature. These properties arise from tourmaline's lack of a centre of symmetry within its trigonal crystal structure. Unlike minerals with centrosymmetric structures, tourmaline crystals have a polar axis, meaning the two ends of a crystal are physically and electrically distinct. This is why tourmaline crystals are sometimes described as having a positive and a negative end. These properties have made tourmaline group minerals the subject of genuine scientific and industrial interest, with applications in pressure sensors and thermal detection instruments. Relationship to Other Tourmaline Varieties Schorl sits within the broader tourmaline group, a complex family of boron silicate minerals that share the same fundamental crystal structure but differ in chemical composition. The variation in colour across tourmaline varieties directly reflects differences in the metal ions present during crystallisation. Schorl (Black Tourmaline) is the iron-dominant species, with high levels of Fe²⁺ producing its opaque black appearance. Elbaite, the species behind Pink, Green, Watermelon, and Indicolite Tourmaline, is lithium and aluminium dominant, producing the vivid transparent colours prized in gemstones. Rubellite is the red to pink gem variety of Elbaite, one of the most prized of all tourmaline varieties. Dravite is the magnesium-dominant species, typically producing brown to dark yellow tones. Uvite is calcium and magnesium dominant, often appearing dark green to black. All tourmaline varieties share the same trigonal crystal habit and boron silicate ring structure. The colour differences are entirely a consequence of which metal ions occupy specific positions within that structure during formation. For a deeper look at two of Schorl's closest relatives, see our Green Tourmaline mineral guide and our Rubellite Tourmaline guide. Care and Handling At 7 to 7.5 on the Mohs Hardness Scale, Black Tourmaline is a durable mineral suitable for everyday handling and display. It is harder than most common minerals and will not be scratched by steel. However, it is brittle, meaning it can fracture if dropped or subjected to sharp impact, particularly along the natural striated faces common to tourmaline crystals. Brief water cleansing is generally safe. Prolonged soaking is best avoided to protect any natural surface finish. Store Black Tourmaline separately from harder minerals such as Corundum or Diamond, and keep it away from softer specimens it might scratch during storage. Traditional Associations While this guide focuses on mineralogy, Black Tourmaline is widely used in spiritual and wellbeing practices. It is strongly associated with grounding, protection, and purification, and is traditionally linked to the Root Chakra in crystal healing systems. These associations are based on traditional and cultural use rather than scientific properties. Browse our Black Tourmaline collection to find the right form for your practice. Summary Black Tourmaline (Schorl) is an iron-rich cyclosilicate mineral that forms primarily within pegmatites and metamorphic rocks through boron-rich hydrothermal processes. Its deep black colour, complex chemistry, and scientifically notable piezoelectric and pyroelectric properties make it one of the most mineralogically interesting members of the tourmaline group. For collectors, it offers a window into the chemistry of late-stage igneous crystallisation and the role of boron in mineral formation. For general buyers, it is a striking, durable, and geologically fascinating mineral with a long and well-documented history. As always, our inbox and DMs are open if you would like guidance or simply wish to explore further. Contact us here if you have any questions! Love, Laura Further Reading Understanding Green Tourmaline | Mineral Guide Rubellite Tourmaline: A Journey to Emotional Equilibrium Basic Guide for the Seven Chakras How to Cleanse and Recharge Your Crystals Crystal Grids 101 How to Choose the Right Crystals Based on Their Shapes Advanced Crystal Choosing

on Jan 13 2025

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Rubellite Tourmaline: Why Not All Pink Tourmaline Earns the Rubellite Name

What is Rubellite Tourmaline Mineral Group: Silicate | Category: Cyclosilicate, Tourmaline Group | Formula: (Na,Ca)(Li,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄ | Hardness: 7 – 7.5 (Mohs) Rubellite is the name given to the pink to red gem varieties of Elbaite Tourmaline, one of the most chemically complex and colour-diverse mineral species known to mineralogy. The name derives from the Latin rubellus, meaning reddish, and it has been in use since at least the eighteenth century to distinguish the finest pink and red Tourmaline from the broader range of colours the species produces. Not all pink Tourmaline qualifies as Rubellite: the name is conventionally reserved for material displaying a saturated, stable red to pink colour that retains its character across different lighting conditions, distinguishing it from the paler or more orange-toned pink Tourmalines that shift noticeably between daylight and artificial light. Tourmaline as a mineral group is defined by one of the most complex crystal structures in mineralogy, a boron-bearing cyclosilicate with a formula that accommodates an extraordinary range of elemental substitutions. This chemical flexibility is directly responsible for the fact that Tourmaline occurs in more colours than virtually any other mineral species, with different colour varieties reflecting different combinations of trace elements occupying the multiple structural sites within the crystal. Rubellite sits at the pink to red end of this colour spectrum, its coloration driven primarily by manganese in the Mn³⁺ oxidation state. Formation and Geological Context Rubellite forms almost exclusively in granitic pegmatites, the exceptionally coarse-grained, volatile-rich igneous rocks that crystallise from the final stages of granitic magma as it cools and becomes concentrated in rare elements. Pegmatites are the primary source of gem-quality Tourmaline of all colours, and the specific chemistry of each pegmatite body determines which Tourmaline varieties develop within it. The formation of Rubellite requires a pegmatitic environment enriched in lithium, aluminium, boron, and manganese. Lithium is essential to the Elbaite species of Tourmaline, substituting into specific structural sites and distinguishing Elbaite from other Tourmaline species such as Schorl, the common black iron-bearing Tourmaline, and Dravite, the brown magnesium-bearing species. Manganese provides the pink to red coloration, with higher concentrations and the Mn³⁺ oxidation state producing the deepest, most saturated reds most valued in the gem trade. The specific shade of Rubellite, from pale bubblegum pink through vivid raspberry to deep ruby red, depends on the concentration of manganese, the presence of other trace elements, and the oxidation conditions during crystal growth. Iron, in particular, can shift the colour toward brown or orange tones and is responsible for the colour instability seen in lower grade pink Tourmaline that does not meet the Rubellite standard. The most celebrated Rubellite localities include the pegmatite fields of Minas Gerais in Brazil, which have produced some of the finest and largest gem crystals known. Nigeria has emerged as an increasingly significant source of high quality material in recent decades. Other notable localities include Mozambique, Madagascar, Afghanistan, and the Ural Mountains of Russia, where Rubellite was first brought to the attention of European courts in the eighteenth century and was prized by the Russian Imperial family. Key Physical Properties Property Detail Mineral Group Silicate Category Cyclosilicate, Tourmaline Group Crystal System Trigonal Hardness 7 – 7.5 Mohs Specific Gravity 3.02 – 3.26 Refractive Index 1.624 – 1.644 Birefringence 0.018 – 0.040 Pleochroism Strong: different shades of pink and red Lustre Vitreous Fracture Uneven to conchoidal Cleavage Indistinct Tenacity Brittle Colour Pink, red, raspberry, ruby red Streak White Formula (Na,Ca)(Li,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄ Safe to Cleanse in Water No for rough specimens; yes for gem quality The specific gravity range of 3.02 to 3.26 is variable because the Tourmaline structure accommodates such a wide range of elemental substitutions that the density shifts measurably between specimens of different compositions. The strong pleochroism, showing different shades of pink and red depending on the direction of viewing, is a characteristic feature of Rubellite and is directly relevant to how gem cutters orient the crystal before cutting to achieve the most desirable face-up colour. The Colour of Rubellite: Manganese and the Red-Pink Spectrum The coloration of Rubellite is one of the more nuanced colour stories in gemology, involving not just the presence of a colour-causing element but its specific oxidation state and the influence of other trace elements on the overall result. Manganese is the primary cause of pink and red in Elbaite Tourmaline. Specifically it is manganese in the Mn³⁺ oxidation state that produces the most saturated and stable reds and pinks. This oxidation state absorbs strongly in the green part of the visible spectrum, leaving red and pink wavelengths to dominate. The depth of colour is proportional to the manganese concentration, with higher concentrations producing deeper, more saturated tones. The presence of iron alongside manganese complicates the picture significantly. Iron in the Fe²⁺ state absorbs in the red and near-infrared, introducing brownish or orangey modifiers that push the colour away from the pure pink and red of true Rubellite toward less desirable tones. This is why the Rubellite designation is conditional on colour stability across lighting conditions: material with significant iron alongside manganese will look noticeably different in incandescent light compared to daylight, a phenomenon called colour shift, which disqualifies it from the Rubellite name regardless of how pink it appears under one light source. The finest Rubellite, showing a pure, saturated red comparable to fine Ruby or Spinel with no brownish or orangey modifier, is genuinely rare and commands prices at the upper end of the coloured gemstone market. Rubellite Within the Tourmaline Family The Tourmaline group is not a single mineral species but a family of related species sharing the same fundamental crystal structure but differing in their chemistry across several key structural sites. Understanding where Rubellite sits within this family helps contextualise both its properties and its value. Elbaite is the lithium aluminium species of Tourmaline and the source of virtually all gem-quality coloured Tourmaline. Its lithium content allows it to accommodate the widest range of trace element substitutions of any Tourmaline species, producing the full colour spectrum from colourless through pink, red, orange, yellow, green, blue, violet, and the multicoloured Watermelon Tourmaline in which pink and green zones occur within a single crystal. Rubellite is the name for Elbaite's pink to red colour range. Indicolite is the name for its blue range. Paraiba Tourmaline is the name for the neon blue-green variety coloured by copper, found originally in Paraiba state in Brazil and subsequently in Mozambique and Nigeria. Schorl is the iron-bearing, black Tourmaline species, by far the most abundant Tourmaline in the crust and found in granites and pegmatites worldwide. Dravite is the magnesium-bearing brown to yellow-brown species. Uvite is a calcium magnesium species. Each shares the fundamental Tourmaline crystal architecture while differing in the specific elements occupying the various structural sites. The Tourmaline group as a whole demonstrates more clearly than almost any other mineral family how a single crystal structure, given sufficient chemical flexibility, can produce an entire spectrum of colours and compositions from the same fundamental atomic architecture. For the green end of this spectrum, see our guide to Green Tourmaline. Pleochroism in Rubellite Rubellite displays strong pleochroism, meaning its colour changes noticeably when viewed from different directions. In Tourmaline, the pleochroism is dichroic rather than trichroic, reflecting the trigonal crystal system which has one unique optical axis rather than three. In Rubellite this typically manifests as a deeper, more saturated pink or red when viewed down the length of the crystal along the c-axis, and a paler or slightly differently toned pink when viewed perpendicular to it. This pleochroism is directly relevant to cutting decisions. Most gem cutters orient Rubellite so that the table facet of the finished stone faces down the c-axis, displaying the deepest colour face-up. The paler pleochroic colour is oriented toward the pavilion where it is less visible in the finished gem. Understanding this explains why the same rough crystal can produce stones of noticeably different apparent colour depending on how it was cut. For collectors of rough Rubellite crystals, rotating a transparent specimen slowly in directional light will reveal the pleochroic colour shift clearly, with the deepest red or pink visible when looking directly down the length of the crystal. For a deeper explanation of how pleochroism works across mineral species, see our guide to Pleochroism in Gemstones. Care and Handling Rubellite is one of the more durable gem minerals available, with a hardness of 7 to 7.5 providing good resistance to everyday wear and an indistinct cleavage meaning it does not split preferentially under impact in the way that more cleavage-prone stones do. These properties make it well suited to jewellery use with reasonable care. Water cleansing is not recommended for rough specimens, where natural fractures and surface irregularities can trap moisture and cause long-term surface degradation. Polished gem-quality material is generally safe for brief water contact. Clean set stones with a soft damp cloth and mild soap, rinse thoroughly, and dry immediately. Avoid ultrasonic cleaning for included or fractured material, as vibration can propagate through existing fractures. Keep away from sustained heat and strong UV sources. The manganese-driven colour of Rubellite is generally stable under normal conditions, but prolonged exposure to intense light or heat can affect the oxidation state of the manganese and cause gradual colour change in some specimens. This is not a concern under normal display and wearing conditions but is worth being aware of for long-term preservation of the finest material. Traditional Associations While this guide focuses on the mineralogy of Rubellite Tourmaline, it is widely valued in spiritual and mindful practices for its associations with love, compassion, and emotional healing. In chakra work it is connected to the Heart Chakra, and its deep pink and red tones have long associated it with matters of the heart across many cultural traditions. These associations are rooted in cultural and traditional use rather than scientific properties. For a full exploration of how to work with Rubellite spiritually, see our dedicated spiritual guide. Summary Rubellite is the gem designation for the finest pink to red Elbaite Tourmaline, its colour driven by manganese in the Mn³⁺ oxidation state and its quality defined by the saturation and stability of that colour across different lighting conditions. Formed in lithium-rich granitic pegmatites and found in its finest form in Brazil, Nigeria, Mozambique, and a handful of other localities worldwide, it represents one end of the extraordinary colour spectrum that the Tourmaline group's chemical flexibility makes possible. Its strong pleochroism, vitreous lustre, and good durability make it one of the more rewarding pink gemstones available to collectors and gem enthusiasts, and its complex chemistry rewards the attention of anyone who wants to understand what they are looking at beyond the immediate impression of the colour. Browse our full Rubellite Tourmaline collection. 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 Understanding Green Tourmaline | Mineral Guide Black Tourmaline: The Mineral That Generates Its Own Electricity Understanding Pleochroism: How Crystal Structure Creates Colour Change in Gemstones Tanzanite: The Gemstone Discovered in 1967 That May Run Out Within Your Lifetime Rhodochrosite: Embrace the Warmth of Your Heart Mangano Calcite: The Crystal Embrace of Compassion and Serenity A Beginner's Guide to Mineral Optical Properties A Beginner's Guide to Mineral Chemical Properties and Classification

on Mar 01 2025

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