State by State


  • Specimen Number


  • Description

    Round cobble of olivine basalt likely from a pocket beach. Voids resembling vesicles are heterogeneous and not aligned, suggesting they result from weathering of less resistant minerals. Bright green minerals in two voids are visible in the upper right portion of the close-up.  They appear to be olivine.

  • Classification

    Igneous. Volcanic. Basalt. Vesicular.

  • Location & Occurrence

    Unusually coarse grained for a basalt.

  • Geological Age

    Likely a million years or less, depending on location.

  • Geoheritage

    Hawaii has the simplest geology of any state. The islands are  mountains of lava flows being eroded by fluvial processes with the the shorelines eroded by wave action and fringed by coral.

  • Links

    Link to State Geological Map from USGS.  Link to Hawaiian Volcanoes Observatory.

  • Other

Click here for an explanation of categories and illustrations

Specimen stone for Hawaii.
Hawaii Closeup Photo. Outline map of Hawaii. Geo Map of Hawaii.