hand sample of pegmatite with metric ruler

black burgandy caco3 calcite cleavage collection college collegiate cooling crust crystals curriculum dark deep dull earth environment formation geo geology geoscience golden hand hardness hobby hornblende identification igneous instrument intergrown intrusive laboratory lithosphere magma melt metric minerals model natural naturally objects occurring pegmatite plutonic properties pyrite red rock ruler sample scale school science sheets shiny slow solidification specimen specimens stone thin transparent white