sand - large-grained quartz dune sand from Monastery Beach, Carmel Bay, California in a 250 ml display bottle with ground glass stopper This mine is the probable

This mine is the probable source of fibers that served as reference standards used since around 2000 by the Health and Safety Laboratory (UK)

then roughly 160 million years later weathers to become sand again which locally forms dunes

a student can see the frosted surface

the immediate zone around the now crystal-lined bubble is altered and becomes more resistant than the surrounding rock and subsequently weathers out

The oldest radiolarian fossils in the cherts lived about 200 million years ago

sand - large-grained quartz dune sand from Monastery Beach, Carmel Bay, California in a 250 ml display bottle with ground glass stopper This mine is the probableThis sand is interesting because of the large size of its quartz grains for a dune sand. Monastery Beach is fed sand immediately by San Jose Creek and by the Carmel River farther north. The longshore current that moves sand from north to south along Californias coast contributes to this beach, but the size and irregular shapes of these grains tells us that the primary source must be a local and not particularly long drainage, most likely San Jose