British Selenite Crystal London Clay Isle of Sheppey Kent UK Specimen

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

This 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 clarity, structure, and strong geological provenance. 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 from this historic locality.

Mineral Species & Crystal Structure

Selenite is a transparent to translucent crystalline variety of gypsum, composed of calcium sulphate dihydrate with the chemical formula CaSO₄·2H₂O. It crystallises in the monoclinic crystal system and commonly forms elongated prismatic or blade-like crystals with well-developed cleavage.

Gypsum has a Mohs hardness of 2, making it a relatively soft mineral. Selenite is recognised for its pearly to vitreous lustre and may display a silky sheen due to its fibrous internal structure. Perfect cleavage in one direction allows smooth reflective surfaces to form naturally.

Crystals from the Isle of Sheppey often show defined growth lines and internal transparency characteristic of slow crystallisation within compacting clay sediments.

Geological Formation – London Clay, Eocene Age

The London Clay Formation dates to the Early Eocene, approximately 56–47 million years ago. During this time, southern England was covered by a warm, shallow marine environment. Fine clay sediments accumulated on the seabed, preserving marine fossils and creating the conditions necessary for mineral growth.

Selenite crystals formed within these marine clays through diagenetic processes. As mineral-rich groundwater moved through the compacting sediment, calcium sulphate precipitated and crystallised in voids and fractures within the clay matrix.

The Isle of Sheppey is internationally known for its Eocene deposits, particularly fossil wood, marine fossils, and mineral specimens. Selenite crystals from this formation are prized for their locality significance and geological age.

Colour, Transparency & Natural Features

This specimen displays natural translucent to semi-transparent clarity typical of selenite from the London Clay. Subtle internal inclusions of clay or growth zoning may be visible, reflecting its sedimentary origin.

Natural surface features, including minor edge wear or matrix traces, are consistent with extraction from clay deposits and confirm authenticity. No dyes, stabilisers, or artificial enhancements have been applied.

The crystal’s light-transmitting quality allows it to softly diffuse illumination, enhancing its visual appeal when displayed.

Collecting, Display & Educational Value

A British selenite crystal from the Isle of Sheppey offers both aesthetic and historical significance. It represents a tangible piece of Britain’s Eocene marine past and is an excellent addition to collections focused on UK minerals or sedimentary geology.

Its monoclinic structure and evaporite mineral formation make it suitable for educational use in demonstrating mineral crystallography and diagenetic processes.

In some traditions, selenite is traditionally associated with clarity and reflection; however, it is primarily valued as a naturally formed gypsum crystal and a classic example of mineral growth within marine sediment.

Authenticity & Presentation

• Genuine 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 selenite crystal representing the marine sedimentary history of the London Clay and the geological heritage of the Isle of Sheppey.