Tanzanite Crystals- 7.5 g - (15)

BASIC DESCRIPTION

Professional-grade lot of 37.5+ ct (15 pieces) of Unheated Fancy Tanzanite (natural Zoisite) crystals, sourced from the world-famous Merelani Hills, Tanzania. This authentic collection of unpolished specimen is characterized by its 100% natural, unheated state, showcasing a rare "fancy" color palette ranging from champagne and olive-green to honey-bronze and lavender-blue. Furthermore, the color of these crystals is an direct evidence that they have not been subjected even to any natural thermal alteration.

Tanzanite is a "single-source" mineral, found only in a small area near the Lelatema Mountains. This specific lot was recovered from the metamorphic veins of the Merelani district. Unlike common heated material, these specimens exhibit the full geological spectrum of the mineral, including minor Graphite inclusions and surface textures typical for primary deposit crystals, confirming their origin and absolute authenticity.

Ideal for gemstone collectors, mineral enthusiasts, or "rough luxury" jewelry designers, this lot showcases the raw, powerful beauty of one of the rarest gemstones on Earth in its most natural form.

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LOT DETAILS

Number of Items: 15

Approx. Total Weight (in carats): 37.5 ct

Approx. Individual Weights (in carats): 3.55; 3.35; 2.95; 2.70; 2.65; 2.60; 2.35; 2.30; 2.30; 2.25; 2.25; 2.25; 2.25; 2.10; 2.00

Color: Multi-colored / Fancy; Pleochroic hues of Golden-Brown, Olive, Honey, and Lavender.

Clarity: Transparent (Facet grade) to Translucent (Cabbing or specimen grade).

Luster: Vitreous (Glass-like).

Treatment: 100% Natural - No Heat Treatment. These crystals have not been subjected to any artificial or natural heating, preserving their rare natural pleochroism and geological integrity.

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TECHNICAL DETAILS

Origin: Merelani Hills, Lelatema Mountains, Simanjiro District, Tanzania.

Type: Natural Zoisite (Variety: Tanzanite).

Chemical Classification: Ca2Al3(SiO4)3(OH) (Calcium Aluminum Hydroxy Silicate).

Crystal System: Orthorhombic.

Hardness: 6.0 – 7.0 on the Mohs scale.

Specific Gravity: 3.35.

Refractive Index: 1.691 – 1.700.

Other Optical Properties:

- Strong Pleochroism (Trichroic: Blue, Violet, and Burgundy/Green/Brown). This is the key diagnostic feature—the stones display different colors when viewed from different crystal axes, a feature most prominent in unheated specimens.

- UV Fluorescence: These specimens exhibit a subtle pinkish/reddish glow under Long Wave UV light. This characteristic reaction is a known trait in certain Merelani Zoisites, serving as an additional indicator of their natural origin and unique chemical composition.

NOTE FOR COLLECTORS: The presence of associated minerals like Graphite is a classic mineralogical signature of the Merelani deposits, confirming the authenticity and specific primary deposit origin of this lot.

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THE "GENERATION GEM" & COSMIC RARITY

Tanzanite is a finite geological phenomenon. Current mining data from the Merelani district suggests that the accessible deposits may be entirely depleted within the next few decades, making this a "one-generation" gemstone. Furthermore, its value is protected by an extraordinary geological paradox: while we are entering an era of asteroid mining for common precious metals and minerals, geologists do not expect to find Tanzanite anywhere else in the universe. Its formation required a unique "perfect storm" of tectonic pressure, specific temperatures, and a rare chemical infusion of Vanadium that occurred only in this single 7km strip of the Tanzanian crust. As far as modern science knows, the specific conditions of the Mozambique Belt are unique to Earth, ensuring that even in a future of space exploration, a natural Tanzanite will remain one of the rarest physical objects in human possession.

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HISTORICAL CONTEXT

Tanzanite is a "baby" in the gemstone world, discovered only in 1967 by Ali Juuyawatu and Manuel d'Souza. It was famously named and introduced to the world by Tiffany & Co., who called it "the most beautiful blue stone discovered in 2000 years."

The Merelani Monopoly: Merelani is the only place on the planet where Tanzanite is found. The unique geological conditions required for its formation (the presence of Vanadium in the right metamorphic environment) have not been found anywhere else.

The Legend of the Fire: Local Masai legend says the hills were set ablaze by a lightning strike, and the heat transformed the dull brown crystals on the ground into shimmering blue gems. This lot represents the material before such a transformation—in its raw, "pre-fire" state.

Mining Heritage: Today, Tanzanite mining has reached depths of over 800 meters. Small-scale artisanal mining is becoming increasingly difficult as the government consolidates the area (Wall of Merelani), making raw, unsearched lots more valuable to collectors.

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GEOLOGICAL ORIGIN AND FORMATION

The Mozambique Belt Genesis: Tanzanite formed during the Pan-African orogeny (approx. 585 million years ago). It is the result of regional metamorphism and hydrothermal activity within the Mozambique Belt.

The Vanadium "Cocktail": The unique colors are caused by the presence of Vanadium (V3+) within the Zoisite crystal lattice. In this unheated lot, the Vanadium manifests in a complex array of "fancy" colors that are lost once the stone is heated.

The "B-C-D" Block Connection: These blocks are famous for producing the highest concentrations of gem-quality material. The association with graphite is crucial; the organic carbon in the shale helped reduce the environment, allowing the specific color potential to manifest.

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GEMOLOGICAL PROFILE

Crystallography: Orthorhombic system. While crystals can be perfectly prismatic, they are often found as fragments or nodules due to the "boudinage" effect (tectonic stretching of the rock layers) during the mountain-building process.

The Pleochroism Signature: One of the most distinctive features is that the stone is naturally Trichroic. These unheated stones show three distinct colors, which creates a unique "velvety" depth and complexity not seen in standard heated material.

Internal Characteristics: Typical features include fine liquid-filled "fingerprints," graphite platelets, and occasional needle-like inclusions.

Durability: Tanzanite has one direction of perfect cleavage, meaning it requires a skilled hand for cutting and setting to ensure the stone's longevity.

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MARKET INSIGHTS (2026)

Tanzanite is widely considered an "Investment Stone" due to its limited supply (Generation Stone—the mines are expected to be depleted within decades).

Single Source Premium: Unlike Sapphires or Rubies found on multiple continents, Tanzanite's price is heavily dictated by the local Tanzanian output and government regulation.

Rarity: It is estimated to be 1000 times rarer than diamond.

Pricing (2026 Estimates):

* Raw "Unheated Fancy" material: Growing premium for natural, untreated specimens among purists.
* Rough material with original mineral signatures is increasingly prized by "specimen" collectors and high-end artisanal jewelers.

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METAPHYSICAL & TRADITIONAL LORE

!!! IMPORTANT DISCLAIMER: The seller does not guarantee any medical, healing, metaphysical, magical and/or esoterical properties. The information is for context only. !!!

Birthstone: December (The modern birthstone of choice).

The "Stone of Transformation": Tanzanite is believed to help integrate the mind and heart, allowing for effective communication of one's truth.

Crown & Third Eye: Healers associate the violet-blue ray with the Crown and Third Eye chakras, supposedly enhancing intuition and spiritual perception.

The "Earth Harmony": As a stone born from fire and pressure, these unheated crystals are said to represent the grounding energy of the earth before transformation.

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DEAR COLLECTOR,

Thank you for your interest in our auction. We are keen to provide you with the best services and we treat every shipment with the utmost priority, ensuring a safe journey to your hands.

Pristine Condition: Every specimen undergoes a meticulous manual cleaning process using isopropyl alcohol and water (no ultrasound used) to ensure purity and weight accuracy.

Precision Documentation: We provide exact measurements and weights for every piece, ensuring the description matches the reality of what you receive.

Selection & Storing: Each stone is professionally sorted and ready for immediate display or specific use in your project. Your order arrives in a professional, softly padded protective box, accompanied by detailed description.

The "Thank You" Bonus: We truly value your support. Every delivery includes a curated bonus gift, with its value scaled to reflect the level of your winning bid.

We wish you a successful auction.

- GeoChimes