Garnet in Mica Schist Saint Helier Jersey Metamorphic Mineral Specimen

Genuine Garnet in Mica Schist – Saint Helier, Jersey

This striking Garnet in Mica Schist specimen from Saint Helier, Jersey, is a genuine metamorphic mineral piece carefully selected for quality, crystal visibility and geological interest. The photograph provided shows the exact specimen you will receive. Please refer to the images for full sizing and scale details.

Your crystal includes a Certificate of Authenticity lifetime guarantee generic card confirming its genuine origin and mineral identification.

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Mineral Species & Crystal System

Garnet is a group of silicate minerals with a general chemical formula of X₃Y₂(SiO₄)₃. In metamorphic mica schists, the garnets are most commonly members of the almandine series (Fe₃Al₂(SiO₄)₃), although compositional variation may occur.

Mineral Group: Garnet (likely Almandine dominant)
General Formula: X₃Y₂(SiO₄)₃
Common Species in Schist: Almandine
Crystal System: Isometric (Cubic)
Hardness: 6.5–7.5 on the Mohs scale
Lustre: Vitreous to resinous
Transparency: Transparent to opaque

Garnets crystallise in the cubic system and typically form equant dodecahedral or trapezohedral crystals. In mica schist, they often appear as well-defined reddish-brown to deep red crystals embedded within the foliated host rock.

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Geological Setting – Metamorphic Rocks of Jersey

Jersey forms part of the Armorican Massif and consists largely of Precambrian and Palaeozoic metamorphic and igneous rocks. Garnet-bearing mica schists develop under regional metamorphism, where sedimentary precursor rocks such as shales are subjected to elevated temperature and pressure.

During metamorphism:

• Clay minerals recrystallise into mica (biotite and muscovite)

• Pressure and heat facilitate garnet crystal growth

• Foliation develops due to directed

Garnets in mica schist typically grow as porphyroblasts, meaning they form larger crystals within a finer-grained metamorphic matrix. These crystals may show internal inclusions or zoning that record changes in metamorphic conditions during growth.

Associated minerals in garnet mica schist may include:

• Biotite

• Muscovite

• Quartz

• Feldspar

• Staurolite (in some metamorphic zones)

This geological environment reflects regional metamorphism linked to ancient tectonic activity.

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Physical Characteristics & Notable Features

This specimen may display:

• Deep red to reddish-brown garnet crystals

• Well-formed dodecahedral crystal shapes

• Strong foliation in mica-rich matrix

• Natural surface texture from metamorphic cleavage

The contrast between the dark garnet crystals and the silvery sheen of mica creates a visually appealing mineral specimen. Garnets often stand proud from the schist matrix, highlighting their robust cubic crystal form.

Internal inclusions, minor fractures or natural surface variation are typical features of metamorphic garnet growth and add geological authenticity.

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Collectibility & Geological Interest

Garnet in mica schist from Saint Helier represents a classic example of regional metamorphism within the Channel Islands geological province. Specimens from documented localities such as Jersey carry added value for collectors interested in British and Channel Islands mineralogy.

Collectors appreciate garnet schist for:

• Clearly visible metamorphic crystal growth

• Classic almandine garnet form

• Recognised Jersey locality

• Educational geological significance

Such specimens are ideal for mineral cabinets, teaching collections and collectors focused on metamorphic mineral assemblages.

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Authenticity & Presentation

This Garnet in Mica Schist specimen has been carefully chosen to showcase both the garnet crystal form and the foliated metamorphic host rock. The image shown is of the exact specimen you will receive.

Included with your purchase is a Certificate of Authenticity lifetime guarantee generic card confirming this is a genuine Garnet in Mica Schist specimen from Saint Helier, Jersey.

A classic representation of metamorphic mineral growth, this piece combines striking crystal geometry, geological history and documented locality provenance in one authentic collector specimen.