Extremely Rare Pleochroic Tanzanite Crystal GEMME Quality - UNHEATED - Height: 8.3 mm - Width: 6 mm- 0.33 g - (1)

Exceptional natural, untreated 100% natural rough tanzanite from Tanzania, presenting a remarkable combination of intense blue, transparency, and pleochroism.

Kept in its natural state, this stone offers a particularly authentic view of one of the most fascinating gemological phenomena associated with tanzanite.

Unlike the vast majority of tanzanites on the market, whose color is enhanced by heat treatment, this specimen is offered non-heat-treated, preserving its natural character and the original expression of its color.

Technical specifications

- Stone: Natural tanzanite – blue zoisite variety
- Weight: 1.63 carats
- Dimensions: 8.3 × 6.0 × 4.1 mm
- Origin: Tanzania
- Color: Intense blue
- Optical phenomenon: Strong pleochroism
- State: Natural rough
- Treatment: No heating
- Naturalness: 100% natural
- Quality: Premium / collection selection

A particularly captivating natural color

This crystal immediately stands out with its intense blue, which, depending on orientation and lighting conditions, ranges from deep blue to blue-violet hues.
This chromatic richness is directly linked to the pleochroism of tanzanite: when the crystal is observed along different axes, light interacts differently with its crystalline structure and reveals several color expressions.
On this specimen, this phenomenon greatly contributes to its character. The stone seems to change appearance as it is turned, shifting from areas of electric blue to cooler or purplish tones, while its natural surfaces produce powerful flashes of light.

Untreated: color as nature created it

One of the main interests of this tanzanite lies in its untreated state.
Heating is commonly used in the tanzanite trade to modify certain natural chromatic components and to favor a blue to blue-violet appearance. A rough tanzanite naturally exhibiting a beautiful blue color while remaining unheated thus has particular appeal for collectors seeking specimens with as natural a character as possible.
Here, the stone is valued precisely for that: no thermal transformation has altered its natural chromatic expression.

A gemstone from a single territory in the world

The story of tanzanite is extraordinary. Commercially discovered in the 1960s, it derives its name from Tanzania, the country with which its gemological existence remains closely tied.
What fundamentally distinguishes tanzanite from many other gemstones is its extreme geographic concentration: economically important deposits are anchored to a very restricted area in northern Tanzania, in the Merelani region near Kilimanjaro.
This dependence on a single region is one of the major factors in the gem’s rarity. Mining production is limited and irregular, and supply of fine crystals cannot be considered unlimited.

An exceptional geological rarity

It is often said that tanzanite is “a thousand times rarer than diamond.” This phrase is primarily a commercial comparison of geological availability, not a universal gemological measure of rarity.
However, the essential fact is indisputable: diamonds are mined in many parts of the world, whereas the gem tanzanite comes from a geographically extremely restricted area in Tanzania.
It is this exceptional concentration that makes its geological history so unique. Available quantities of fine-quality tanzanite are necessarily tied to the production of this sole region, and crystals combining beautiful natural color, transparency, strong pleochroism, and no heating constitute a highly sought-after category.

A spectacular rough specimen

The morphology of this piece is also noteworthy.
Its natural surfaces feature numerous reliefs, striations, and crystal planes that catch the light in a spectacular way. Some areas are very transparent and luminous, while others reveal the complexity of the crystal’s natural growth.
The contrast between its saturated blue, almost electric blue zones, and its silvery reflections gives it a remarkable visual presence under direct lighting.
Preserving this rough specimen also preserves all this natural architecture, which would largely disappear if transformed into a faceted stone.

A tanzanite for a discerning collection

This piece brings together several highly desirable characteristics: Tanzanian origin, 1.63 carats, intense blue color, strong pleochroism, rough state, and above all, no heating.
It thus makes a superb specimen for a collection of natural gems, Tanzanian minerals, or crystals exhibiting remarkable optical phenomena.

The future rarity of a deposit cannot be guaranteed with precision, so no financial guarantee can be promised. Nevertheless, the extreme geographic concentration of tanzanite and the particular interest in beautiful untreated specimens give this stone genuine patrimonial and collectible value.

A tanzanite with character, preserved as nature formed it, uniting color, transparency, pleochroism, and authenticity in a specimen for the most demanding collectors.


General Terms and Conditions of Sale – MineralsOpals:

At MineralsOpals, your satisfaction is a top priority.
All orders are handled with the utmost care, from stone selection to final shipment.

- Shipping & timelines:
Shipping within 1 to 3 business days maximum, usually the day after the order.
Shipping from Monday to Friday (excluding weekends and holidays).
Each package is sent via La Poste with a tracking number provided.
Careful packaging: each stone is individually protected, then placed in a secure rigid carton.

- Guarantee & customer service:
100% of shipments are guaranteed: in case of any issue, we always find a solution.
Shop with confidence: full refund, replacement, or a goodwill gesture in case of loss or proven problem.
If you have a question, doubt, or specific request, you can contact me at any time; I will respond gladly as soon as possible.

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