State by State


  • Specimen Number


  • Description

    Cut and polished block of dimension stone composed of coarse-grained pink granite.  State survey staff identifies this as Pikes Peak granite, a syenogogranite composed of pink microcline, quartz, hornblende, and biotite.

  • Classifications

    Igneous. Plutonic. Granitic. Syenogranite.

  • Location & Occurrence

    Potassic pluton from anorogenic Pikes Peak batholith, almost certainly the Pikes Peak Formation. The coarse grain texture and uniformity indicate slow stable cooling at significant depth.

  • Geologic Age

    Proterozoic, ~ 1 billion  years old (Ga).

  • Geoheritage

    Highest peak in the Mountain State.  Massive granite batholiths float high in the crust, especially after Cenozoic de-lamination of lithosphere.  Being deeply rooted and low-density, they float high. Closeup shows classic granitic texture.

  • Links

    Link to State Geological Map from USGS.  Link to State Geological Survey.

  • Other

    Credit State Survey.

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Specimen stone for Alaska.
Closeup of Colorado Outline map of Colorado Geo Map of Colorado