State by State
- Specimen Number
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.
Igneous. Volcanic. Basalt. Vesicular.
Location & Occurrence
Unusually coarse grained for a basalt.
- Geological Age
Likely a million years or less, depending on location.
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.