This specimen contains rutile crystals with a metallic luster that formed within a pyrophyllite matrix. It was collected from the Champion Mine within the White Mountains of California.
Rutile is an oxide mineral that is composed primarily of TiO2, although iron is a typical chemical variation. It comes in a wide variety of crystal forms, from lustrous metallic-like crystals, thin straw like crystals, to even deep red crystals with slight translucence. Rutile has also been know to form needle-like inclusion with other minerals, commonly forming with quartz. Rarer polymorphs of rutile (TiO2) include anatase and brookite, both of which have unique crystal structures.