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1.4" Goethite Pseudomorph after Pyrite Iron Cross Twin - Colombia
This is a 1.4" wide pyrite "iron cross twin" specimen that was collected from the Guavió-Guatéque Mining District of Colombia. These twinned pyrite crystals are pentagonal dodecahedrons that underwent surface alteration to goethite, giving the exterior of the crystals their dark color.
About Goethite Iron Crosses
Goethite iron cross twins are rare and visually striking formations of the mineral goethite, an iron-bearing hydroxide with the chemical formula FeO(OH). Goethite is one of the most common iron oxide minerals, typically forming as a weathering product of iron-rich minerals and contributing to the composition of rust and limonite. It usually appears in earthy, massive, or botryoidal forms, but under specific conditions, it can crystallize into sharply defined prismatic crystals.
In the case of iron cross twins, goethite crystals intersect at near-perfect right angles in a formation known as penetration twinning. This creates a distinctive cross-shaped appearance that is both geometrically fascinating and aesthetically dramatic. These twins are most famously found in the Volodarsk-Volynskii region of Ukraine, where unique geological conditions allowed for their formation. With their metallic luster, dark coloration, and unusual symmetry, goethite iron cross twins are highly sought after by collectors and admired for their natural elegance and crystallographic rarity.
Goethite iron cross twins are rare and visually striking formations of the mineral goethite, an iron-bearing hydroxide with the chemical formula FeO(OH). Goethite is one of the most common iron oxide minerals, typically forming as a weathering product of iron-rich minerals and contributing to the composition of rust and limonite. It usually appears in earthy, massive, or botryoidal forms, but under specific conditions, it can crystallize into sharply defined prismatic crystals.
In the case of iron cross twins, goethite crystals intersect at near-perfect right angles in a formation known as penetration twinning. This creates a distinctive cross-shaped appearance that is both geometrically fascinating and aesthetically dramatic. These twins are most famously found in the Volodarsk-Volynskii region of Ukraine, where unique geological conditions allowed for their formation. With their metallic luster, dark coloration, and unusual symmetry, goethite iron cross twins are highly sought after by collectors and admired for their natural elegance and crystallographic rarity.
$39
SPECIES
Goethite & Pyrite
LOCATION
Gachalá Municipality, Guavió-Guatéque Mining Dist., Cundinamarca Dept., Colombia
SIZE
1.4" wide
CATEGORY
ITEM
#295105
