calcite - teaching hand/display specimen of massive naturally-brown calcite coastal upwelling and areas of

coastal upwelling and areas of biosiliceous productivity that occurred at that time

The angular nature of these grains shows that transport was short

forming a layer cake of silty sediment and peat

This type of chert is a sedimentary rock

The frosted quartz grains are characteristic of the Navajo Sandstone - the quartz grains essentially sandblasted each other as they were transported by the wind and deposited in dunes

calcite - teaching hand/display specimen of massive naturally-brown calcite coastal upwelling and areas ofThis calcite is recrystallized from a limestone in contact with a granitic intrusion. The brown color is unusual and is derived from iron in the limestone that was released by the metamorphism. It effervesces in dilute hydrochloric acid (muriatic acid is the same) as does all calcite. The crystals of this calcite are interlocking, so it does not cleave into large rhombs, though individual specimens show many cleavage faces in several directions. The