Pharmacosiderite W Alfred Cornwall Genuine Mineral Specimen with Certificate of Authenticity

Genuine Pharmacosiderite – W Alfred, Hayle, Cornwall, UK

This Pharmacosiderite specimen from W Alfred, also known as Great W Alfred or Alfred Consols, Hayle, Cornwall, England, is a genuine and carefully selected example of classic Cornish secondary mineralisation. The photograph provided shows the exact specimen you will receive. Please refer to the images for full sizing details and accurate scale.

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

Mineral & Geological Classification – Pharmacosiderite

Pharmacosiderite is a hydrated iron arsenate mineral with the general chemical formula KFe₄(AsO₄)₃(OH)₄·6–7H₂O. It belongs to the arsenate mineral group and crystallises in the isometric (cubic) crystal system.

Mineral Name: Pharmacosiderite
Chemical Formula: KFe₄(AsO₄)₃(OH)₄·6–7H₂O
Mineral Group: Arsenate
Crystal System: Isometric
Hardness: 2.5–3 on the Mohs scale
Lustre: Vitreous
Transparency: Transparent to translucent

Pharmacosiderite commonly forms small, well-defined cubic crystals. These cubes may appear sharp and glassy, often displaying a characteristic green to yellow-green colour. Colour variations may range from olive-green to brownish tones depending on composition and oxidation state.

The mineral’s cubic symmetry gives it a distinctive geometric form, making it readily identifiable under magnification.

Geological Setting – W Alfred, Cornwall

W Alfred, located near Hayle in Cornwall, was historically worked for copper and arsenic. The mineralisation is associated with the Cornubian granite batholith, emplaced during the late Carboniferous to early Permian periods. Hydrothermal fluids circulated through fractures and lodes, depositing primary sulfide minerals including chalcopyrite, arsenopyrite and other copper-arsenic species.

Pharmacosiderite forms as a secondary mineral within the oxidised zone of arsenic-rich deposits. As primary arsenic-bearing minerals such as arsenopyrite break down under surface conditions, iron and arsenic combine with potassium-bearing fluids to crystallise pharmacosiderite in open cavities and fractures.

Associated minerals from this locality may include scorodite, olivenite, quartz and iron oxides, reflecting the complex supergene alteration processes typical of Cornish arsenic-rich veins.

Crystal Characteristics & Notable Traits

This specimen may display:

• Small, well-formed cubic crystals

• Green to olive colouration

• Vitreous surface lustre

• Crystals perched on contrasting matrix

Pharmacosiderite crystals are often microscopic to small in size but exhibit strong geometric definition. Under magnification, their cubic habit is clearly visible.

Natural growth patterns, minor matrix attachment and subtle colour zoning are part of the specimen’s geological character and confirm its authenticity.

Geological Importance & Collectibility

Cornwall is internationally recognised for its diverse mineral assemblages and historic mining heritage. Pharmacosiderite from W Alfred is particularly valued by collectors due to the mine’s reputation for arsenate minerals.

The mineral’s formation represents the oxidation stage of arsenic-bearing hydrothermal deposits, offering insight into secondary mineral development in granite-related systems.

Specimens from named Cornish mines carry documented locality value and are desirable additions to mineral cabinets, especially for collectors of British arsenate minerals.

Because this is a genuine natural specimen, each piece displays unique crystal distribution and surface features shaped by its geological environment. The photograph shows the exact specimen you will receive.

Authenticity & Presentation

This Pharmacosiderite specimen from W Alfred has been carefully chosen for crystal definition and locality significance. Included with your purchase is a Certificate of Authenticity lifetime guarantee generic card confirming its genuine origin from Hayle, Cornwall, England, UK.

Combining classic Cornish arsenic-zone mineralisation with sharply defined cubic crystal growth, this specimen offers mineral authenticity, geological importance and strong collector appeal in one carefully selected piece.