EXTREMELY RARE Herkimer Diamond — 11.67 carats Exceptional clarity - NO RESERVE PRICE - Height: 16.5 cm - Width: 13 cm- 2.33 g - (1)

Discover this extraordinary natural 11.67-carat Herkimer diamond, a collector’s specimen that is particularly captivating for its crystalline geometry, beautiful transparency, and remarkable complexity of internal structures.

This piece features magnificent doubly terminated crystallization, characterized by two opposing pyramidal terminations whose natural faces form a particularly elegant geometric silhouette. Its tall, well-defined upper termination contrasts harmoniously with its lower termination, giving the crystal an almost sculptural appearance.

One of this specimen’s most fascinating features lies in its internal structure. Through its many transparent faces, it is possible to observe a veritable network of crystalline veils, natural fractures, and small dark inclusions, creating remarkable visual depth.

Light passes through different areas of the crystal and reflects off its natural faces, producing intense flashes of light. Some areas appear particularly clear, while others reveal a much more complex internal architecture.

Weighing 11.67 carats and measuring a generous 16.5 × 13 × 11.1 mm, this specimen has a remarkable presence. The combination of its two visible terminations, balanced morphology, and transparency—which allows its internal structures to be seen—makes it a particularly interesting piece for collectors of natural crystal formations.

Specimens combining beautiful doubly terminated geometry, expressive terminations, and transparency that reveals their internal structures are particularly prized by collectors. Each crystal is an individual formation, shaped by specific geological conditions and impossible to naturally reproduce in exactly the same way.

This magnificent Herkimer diamond is a doubly terminated quartz specimen, a natural crystal formation that is particularly sought after when it displays such expressive geometry. The name “Herkimer diamond” has historically been used for these doubly terminated crystals, famous for their brilliance and visual resemblance to diamonds, although they belong to a different mineral species.


Technical specifications

- Trade name: Herkimer diamond
- Mineralogical nature: Natural doubly terminated quartz
- Origin: Pakistan
- Weight: 11.67 carats (2.334 grams)
- Dimensions: 16.5 × 13 × 11.1 mm
- Color: Colorless, with slight internal nuances
- Transparency: Transparent to translucent depending on the area
- Crystallization: Doubly terminated, with two opposing pyramidal terminations
- Morphology: Natural crystal with multiple faces
- Luster: Vitreous, with a brilliant sheen on the crystal faces
- Inclusions: Dark inclusions, veils, and natural internal fractures
- Condition: Natural rough crystal
- Hardness: 7 on the Mohs scale
- Intended use: Mineral collection, crystallography, and display


The fascinating history of Herkimer diamonds


The history of Herkimer diamonds is closely linked to one of North America’s most famous geological formations.

Their name comes from Herkimer County, located in the state of New York, United States, where these natural doubly terminated crystals have earned an international reputation.

The rock formations that host them date back approximately 500 million years, to the Cambrian Period.

At that time, complex geological processes led to the formation of cavities in dolomitic rocks. These natural spaces gradually filled with mineralizing fluids, encouraging the growth of crystals with remarkable geometric forms.

What makes these formations distinctive is that some crystals can grow freely within their cavity, without being attached to a matrix at either end.

This particular type of growth can give rise to two opposing terminations, creating a natural morphology of great elegance.

Indigenous peoples knew of these crystals long before they became widespread in modern collections. Their brilliance and transparency gradually contributed to their renown.

With the development of mineralogy and crystal collecting, Herkimer diamonds became iconic specimens, sought after for their natural crystallization and aesthetic appeal.

Today, their name remains associated with a fascinating mineralogical tradition, even though crystals with a comparable morphology are also found in other parts of the world.

The beauty of these formations lies in their apparent geometric perfection, achieved without any human intervention, solely through natural crystallization processes.
An exceptionally elegant double termination
This specimen is distinguished in particular by its two clearly visible pyramidal terminations.

Its upper termination has an elongated silhouette, formed by sloping faces that converge at a natural point.

This geometric architecture is one of the piece’s main attractions.

The lower section reveals a second termination, more complex in appearance but just as interesting from a crystallographic perspective.

Together, they form an almost symmetrical silhouette, reminiscent of the geometric shapes of cut gemstones, even though all the visible faces result from the crystal’s natural growth.

This feature is fascinating: nature has created a structure with precise contours, without mechanical intervention.

The relatively well-developed lateral faces connect the two terminations and allow the crystal’s depth to be appreciated.

Some are beautifully transparent, while others reveal reliefs and growth features.

Under suitable lighting, the terminations catch the light and produce magnificent reflections.

The combination of two expressive points and a transparent central structure gives this specimen a particularly remarkable aesthetic presence.


A fascinatingly complex inner world


Beyond its silhouette, this Herkimer diamond has a particularly interesting internal architecture.

Through its natural faces, one discovers an array of veils, fractures, and inclusions that seem to form a miniature mineral landscape.

Some structures appear as fine, irregular lines, while others form denser areas with silvery reflections.

Small dark inclusions are also visible in several parts of the crystal.

These features bear witness to the natural conditions it experienced during its formation and geological evolution.

Crystals can preserve many traces of their history, particularly in the form of mineral inclusions, growth discontinuities, or internal fractures.

These features are individual characteristics that help distinguish each specimen.

In this piece, the internal structures create a particularly attractive contrast with the more transparent areas.

Light enters the crystal, encounters different internal surfaces, and produces reflections that vary with the viewing angle.

Some areas appear almost silvery, while others reveal deeper transparency.

This visual richness makes the specimen particularly interesting to examine under magnification.

Each angle reveals a new arrangement of its internal structures, offering a genuine exploration of the crystal’s natural architecture.


A geological formation shaped under particularly demanding conditions


The growth of a doubly terminated crystal requires a favorable environment that allows two opposing terminations to develop.

Unlike crystals that form directly on a rock surface, some specimens can grow in cavities that offer enough space for growth in several directions.

Formation begins when fluids containing the elements needed for crystallization circulate through these spaces.

Under certain conditions of temperature, pressure, and chemical composition, the dissolved elements begin to arrange themselves into a regular crystal structure.

This growth can continue over long geological periods.

Changes in the environment gradually influence the crystal’s shape, the arrangement of its faces, and its internal characteristics.

Changes in fluid circulation, the availability of mineralizing elements, or mechanical stresses can also leave traces in its structure.

The development of two well-formed terminations is therefore a particularly interesting phenomenon.

When this morphology is combined with beautiful transparency and expressive geometry, the result can be spectacular.

This specimen is a remarkable illustration of these natural processes.

Its doubly terminated silhouette and numerous internal structures bear witness to a complex geological history, inscribed directly in the crystalline material.


A remarkable 11.67-carat specimen


At 11.67 carats, this Herkimer diamond has a particularly impressive weight for an individual piece.

Its dimensions of 16.5 × 13 × 11.1 mm give it generous volume, making its various features easy to observe.

Its 11.1 mm depth is particularly interesting, as it contributes to the crystal’s three-dimensional presence.

Unlike flatter specimens, this piece has a substantial structure that highlights its various faces.

Its two opposing terminations are naturally its most remarkable features.

They create a balanced silhouette that is instantly recognizable and particularly attractive.

The transparency of several faces also makes it possible to appreciate the richness of its internal structures.


Among this piece’s most appealing features:

- Magnificent natural doubly terminated crystallization.
- Two expressive pyramidal terminations.
- An elegant, balanced geometric silhouette.
- Beautiful transparency across several areas of the crystal.
- Numerous brilliant natural faces.
- A particularly complex internal architecture.
- Fascinating inclusions and crystalline veils.
- Intense flashes of light under suitable lighting.
- A remarkable weight of 11.67 carats.
- Generous dimensions of 16.5 × 13 × 11.1 mm.
The combination of these features gives this specimen a particularly appealing visual identity and genuine interest for crystallography enthusiasts.


An exceptional collector’s piece


Mineral collectors are particularly drawn to crystals with expressive morphology and beautiful crystallization.

Doubly terminated specimens hold an important place in this field because their natural geometry makes it possible to appreciate the laws of crystal growth directly.

Some examples are prized for their almost perfect clarity.

Others attract attention through their inclusions, internal architecture, or morphological features.

This Herkimer diamond brings together several of these qualities.

Its double termination gives it a particularly attractive silhouette, while its transparency allows many internal structures to be observed.

The complexity of its crystallization also adds to its mineralogical interest.

Displayed in a cabinet, this specimen naturally draws the eye with its geometric shape and numerous reflective surfaces.

Directional lighting can highlight its terminations and gradually reveal details of its architecture.

It is therefore a particularly interesting piece for adding to a natural crystal collection.

A distinctive specimen, combining a remarkable visual presence with all the fascination of natural mineral formations.


Conclusion – An extraordinary natural 11.67-carat Herkimer diamond


This magnificent natural 11.67-carat Herkimer diamond, measuring 16.5 × 13 × 11.1 mm, stands out for its remarkable double termination, beautiful transparency, and exceptionally rich internal structures.

Its two opposing pyramidal points, elegant geometric silhouette, and numerous brilliant faces give it a particularly appealing appearance.

The natural inclusions and crystalline veils visible inside add another dimension to its mineralogical interest.

Every detail bears witness to the complex geological phenomena that contributed to its formation.

A superb collector’s piece, remarkable for the elegance of its doubly terminated crystallization, the richness of its internal architecture, and the authentic beauty of its natural forms.




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