Iron Cross Pyrite Twin
$56.00
This is a rare formation of Pyrite known sometimes as a "Twin Cross" or "Iron Cross" due to its unique twinning formation of two pentagonal dodecahedra. I'm going to get science-y here for a second, because these are cool and you might be interested in how these form.
A twin crystal consists of two or more individual crystals joined together along a common plane, rotated around a common axis or inverted around a common point. This is different than an intergrown group or cluster of crystals simply joined together as it requires a defined crystallographic relationship between the crystals comprising the twin. An Iron Cross Twin falls in the second category. Is a kind of penetration twin that consists of interpenetrated pyritohedra. A classic Iron Cross Twin appears as if one pyritohedron, rotated 90 degrees, is fused at the core of another pyritohedron.
But why aren't they gold toned like pyrite is normally? Well, because they are an alteration pseudomorph, which means the faces of the pyrite has been replaced with goethite, which gives it that black gunmetal sheen with a hint of red all over the surface. Cool.
Origin :: Gachala, Colombia
Measurements :: 39 x 38 x 36 mm
Weight :: 3.4 oz
A twin crystal consists of two or more individual crystals joined together along a common plane, rotated around a common axis or inverted around a common point. This is different than an intergrown group or cluster of crystals simply joined together as it requires a defined crystallographic relationship between the crystals comprising the twin. An Iron Cross Twin falls in the second category. Is a kind of penetration twin that consists of interpenetrated pyritohedra. A classic Iron Cross Twin appears as if one pyritohedron, rotated 90 degrees, is fused at the core of another pyritohedron.
But why aren't they gold toned like pyrite is normally? Well, because they are an alteration pseudomorph, which means the faces of the pyrite has been replaced with goethite, which gives it that black gunmetal sheen with a hint of red all over the surface. Cool.
Origin :: Gachala, Colombia
Measurements :: 39 x 38 x 36 mm
Weight :: 3.4 oz