Staurolite Crystal Kerzest Coray Finistere France Natural Cross Twin Mineral 10-40mm Genuine Collector Specimen with Certificate

Staurolite Crystal – Kerzest, Coray, Finistère, France

This genuine Staurolite crystal specimen comes from Kerzest, near Coray in Finistère, Brittany, France — a classic European locality for well-formed staurolite crystals. Carefully selected for crystal form and mineral character, each specimen measures approximately 10–40mm. The photograph shows an example of the actual specimen you will receive. Please refer to the images for full sizing and natural variation within this range.

Your Staurolite specimen includes a Certificate of Authenticity lifetime guarantee generic card, confirming it is a 100% genuine natural mineral from France.

Mineral Species & Chemical Composition

Staurolite is an iron aluminium silicate mineral with a complex chemical formula typically expressed as:

(Fe,Mg)₂Al₉Si₄O₂₃(OH)

It belongs to the nesosilicate mineral group and crystallises in the monoclinic crystal system. One of the most distinctive features of Staurolite is its frequent penetration twinning, forming cross-shaped crystals. These natural cross formations are highly prized by collectors and are a defining characteristic of the species.

Key mineralogical properties include:

• Mineral Group: Nesosilicate

• Crystal System: Monoclinic

• Typical Crystal Habit: Prismatic, commonly twinned at 60° or 90°

• Colour: Reddish-brown to dark brown

• Lustre: Vitreous to resinous

• Hardness: 7–7.5 on the Mohs scale

• Transparency: Opaque to translucent on thin edges

Geological Formation – Brittany, France

The Staurolite from Kerzest, Coray forms in medium- to high-grade metamorphic rocks, particularly mica schists and gneisses. These rocks developed under significant heat and pressure during regional metamorphism associated with ancient tectonic events in the Armorican Massif.

Staurolite typically forms during metamorphism of aluminium-rich sedimentary rocks, where iron and magnesium are incorporated into its crystal structure. It is commonly associated with minerals such as garnet, kyanite, mica, quartz, and andalusite.

The Brittany region is well known for producing well-developed staurolite twins, making it an important locality for collectors of European metamorphic minerals.

Crystal Form & Appearance

Staurolite crystals from this region often display classic cross-shaped twins, formed by two intergrown crystals intersecting at characteristic angles. Individual crystals may appear as prismatic forms or partially embedded in mica-rich matrix.

The natural reddish-brown to dark chocolate tones are typical of iron-bearing staurolite. Surface texture may range from smooth crystal faces to slightly weathered edges depending on natural exposure. No artificial treatment or enhancement has been applied beyond careful cleaning.

Each specimen in the 10–40mm size range offers a compact yet visually distinctive example of this iconic metamorphic mineral.

Collecting & Historical Interest

Staurolite has long been valued by mineral collectors for its distinctive cross-shaped twinning. In some cultural traditions, naturally twinned staurolite crystals have been regarded as symbolic objects; such associations are spiritual and historical rather than scientific.

Specimens from Kerzest, Coray are particularly desirable due to their defined crystal habits and well-documented geological setting. This makes them suitable for:

• Metamorphic mineral collections

• Crystal system study displays

• European locality collections

• Educational geology sets

The combination of structural uniqueness, geological significance, and French locality makes this specimen especially appealing to serious mineral enthusiasts.

Authenticity & Individual Selection

Each Staurolite crystal is a carefully chosen genuine specimen from Kerzest, Coray, Finistère, France. The listing photograph shows an example of the actual specimen you will receive within the stated 10–40mm size range. Please review all images for scale and natural variation in crystal form.

Every specimen is supplied with a Certificate of Authenticity lifetime guarantee generic card, confirming its genuine natural origin.

A classic example of French metamorphic mineralisation, this Kerzest Staurolite crystal represents a striking natural twin formation and a distinctive addition to any serious mineral collection.