hand sample of rounded porphorytic textured rock with red matrix

identification solidification mineralization amygdaloidal environment metamorphic sedimentary volcanology collecting geological geoscience unpolished mineralogy department amygdaloid keweenawan coastline collector curiosity education formation inclusion resistant vesicular vesicules petrology abrasion exemplar particle rounding sediment lapidary porphory michigan rhyolite interior superior volcanic geodesic coastal fluvial geology igneous mineral science texture washing pattern rounded abraded curious olivine pockets action pebble washed design stones royale basalt quartz geodes coast earth holes holey sized feldspar stony polka dot pattern large crystals crystalline crack joint