Description
Large Natural Selenite Crystal from the Isle of Sheppey, Kent
This impressive large Selenite crystal from the Isle of Sheppey in Kent, United Kingdom is a genuine mineral specimen showcasing the distinctive clarity and structure typical of this well-known variety of gypsum. Carefully selected for its natural form and mineralogical character, this specimen represents a classic example of evaporite mineral formation from southeastern England.
The crystal shown in the photographs is the exact specimen you will receive, making it a unique and individually identifiable mineral piece. This specimen includes a Certificate of Authenticity lifetime guarantee generic card, confirming that the crystal is a genuine natural mineral specimen.
Please refer to the photographs for full sizing and scale of the crystal.
Mineral Identification – Selenite
Selenite is a transparent to translucent crystalline variety of gypsum, a hydrated calcium sulfate mineral with the chemical formula CaSO₄·2H₂O. Gypsum forms in the monoclinic crystal system and is well known for producing elongated, blade-like crystals with a silky or glassy appearance.
The name “selenite” derives from the Greek word selene, meaning moon, referring to the mineral’s soft pearly sheen and luminous appearance. Selenite crystals are typically colourless to milky white and can exhibit delicate internal structures created during crystal growth.
Typical characteristics of natural selenite crystals include:
- Elongated prismatic or blade-like crystal habit
- Transparent to translucent crystal structure
- Smooth, reflective cleavage surfaces
- Fibrous or striated internal textures
- Soft mineral hardness characteristic of gypsum
Because gypsum has perfect cleavage and a relatively low hardness, selenite crystals often display smooth natural faces and a soft satin-like lustre.
Geological Origin – Isle of Sheppey, Kent
The Isle of Sheppey, located along the north coast of Kent, is a historically important geological locality known for its fossil-rich coastal exposures and mineral specimens. The island is famous for its Eocene London Clay deposits, which were formed around 50 million years ago in a warm marine environment.
Within these clay-rich sediments, mineral-rich waters circulated through pore spaces and fractures in the rock. Under suitable chemical conditions, dissolved calcium and sulfate ions combined and crystallised as gypsum. Over time, these crystals developed within cavities and sediment layers, forming selenite specimens like this one.
The coastal cliffs and beaches of the Isle of Sheppey have long been known to produce natural mineral specimens alongside fossils such as marine vertebrates, plants, and invertebrates preserved within the London Clay Formation.
Crystal Habit and Physical Characteristics
Selenite crystals are prized for their elegant and delicate crystal habit. Specimens often grow as elongated blades or tabular crystals, sometimes forming clusters or individual crystal points depending on the conditions of formation.
The large crystal presented here displays typical mineralogical features including:
- A well-developed elongated crystal structure
- Natural translucent gypsum composition
- Smooth cleavage faces reflecting the crystal’s internal structure
- Subtle internal growth patterns visible within the crystal body
These characteristics make selenite specimens visually distinctive and highly recognisable among collectors of evaporite minerals.
Formation Environment
Gypsum minerals such as selenite typically form in evaporitic environments, where mineral-rich water gradually evaporates and dissolved minerals crystallise out of solution. These environments may include marine basins, lagoons, or sedimentary basins where water chemistry allows calcium sulfate minerals to precipitate.
In sedimentary deposits like those found in Kent, gypsum crystals can form within clay-rich sediments where groundwater circulation provides the chemical components necessary for crystal growth.
Over time, these crystals remain preserved within the surrounding sediment until natural erosion or coastal exposure reveals them.
Collector and Display Information
- Mineral: Selenite (variety of Gypsum)
- Chemical Formula: CaSO₄·2H₂O
- Mineral Group: Sulfate minerals
- Crystal System: Monoclinic
- Crystal Habit: Elongated blade-like crystal form
- Locality: Isle of Sheppey, Kent, United Kingdom
- Geological Context: Associated with Eocene sedimentary deposits of the London Clay Formation
- Specimen Type: Natural large selenite crystal
- Authenticity: 100% genuine mineral specimen
- Documentation: Includes Certificate of Authenticity lifetime guarantee generic card
This large natural selenite crystal from the Isle of Sheppey makes an excellent addition to any mineral collection, geological display, or natural specimen cabinet. With its distinctive crystal habit and classic British locality, it represents a beautiful example of gypsum mineral formation and a striking specimen for collectors of UK minerals and sedimentary crystal growth.
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