Giant British Selenite Crystal London Clay Isle of Sheppey UK Specimen

Giant British Selenite Crystal – London Clay, Isle of Sheppey, Kent, UK

This Giant British Selenite crystal originates from the London Clay Formation of the Isle of Sheppey, Kent, UK, dating to the Eocene Epoch. It is a genuine natural mineral specimen, carefully selected for its impressive size, clarity, and historic geological context. The photographs in the listing show the exact specimen you will receive. Please refer to the images for full sizing and scale details.

Each crystal includes a Certificate of Authenticity lifetime guarantee generic card, confirming it as a genuine British selenite specimen.

Mineral Species & Crystal Structure

Selenite is a transparent to translucent crystalline variety of gypsum, with the chemical formula CaSO₄·2H₂O (calcium sulphate dihydrate). It crystallises in the monoclinic crystal system and commonly forms elongated prismatic or tabular crystals with a pearly to vitreous lustre.

Gypsum has a Mohs hardness of 2, making it a relatively soft mineral that can be gently scratched with a fingernail. Selenite is known for its fibrous internal structure, silky sheen, and in some cases a subtle chatoyant effect caused by parallel crystal fibres.

The crystal habit of Isle of Sheppey selenite often reflects slow growth within clay-rich sedimentary environments, producing well-defined elongated forms.

Geological Formation – London Clay, Eocene Epoch

The London Clay Formation dates to the Early Eocene, approximately 56–47 million years ago. During this period, much of what is now southern England was covered by a warm, shallow subtropical sea.

Selenite crystals formed within the fine-grained marine clay sediments through evaporitic and diagenetic processes. As mineral-rich waters circulated through compacting clay, calcium sulphate precipitated and crystallised in voids and fissures within the sediment.

The Isle of Sheppey is internationally recognised for its Eocene fossil beds and mineral occurrences. Large selenite crystals from this formation are particularly sought after due to their size, locality significance, and connection to Britain’s marine geological history.

Colour, Transparency & Natural Features

This giant selenite crystal displays natural translucent to semi-transparent clarity, with soft internal light transmission characteristic of gypsum. Subtle internal growth lines, inclusions of clay matrix, or minor surface weathering are normal features reflecting its sedimentary origin.

The crystal may exhibit natural striations, cleavage planes, or slight edge wear consistent with extraction from clay deposits. These characteristics confirm its authenticity and geological age.

No artificial treatments, dyes, or enhancements have been applied.

Collecting, Display & Historical Interest

A large selenite crystal from the London Clay is both a mineral specimen and a tangible piece of Eocene Britain. Its connection to a well-documented geological formation enhances its scientific and educational value.

The size and clarity make it an impressive display piece for collectors of British minerals, sedimentary geology enthusiasts, or those specialising in Eocene material.

In some traditions, selenite is traditionally associated with clarity and purity; however, it is primarily valued as a naturally formed gypsum crystal and an important example of sedimentary mineral formation.

Authenticity & Presentation

• Genuine Giant British Selenite Crystal
• London Clay Formation, Isle of Sheppey, Kent, UK
• Eocene Epoch (approx. 56–47 million years old)
• Gypsum (CaSO₄·2H₂O)
• Monoclinic crystal system
• Natural, untreated mineral specimen
• Exact specimen shown in listing photographs
• Includes Certificate of Authenticity lifetime guarantee generic card
• Full measurements available in listing images

A carefully selected giant selenite crystal representing the marine sedimentary history of Eocene Britain and the distinctive mineralogy of the London Clay Formation.