A quick way to identify sandstone on beach vacations

Last summer at the Oregon coast, I noticed how sandstone cliffs erode into smooth, rounded shapes. By feeling the gritty texture and seeing the layered look, I could point it out to my friends without any tools. What are some other hands-on clues for common rocks at the shore?

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3 Comments

parkerw147mo ago

Hold up, I gotta disagree a bit here. Sandstone isnt always gritty or layered like that. Ive found pieces so smooth from wave action that they feel almost slippery, with no clear layers. The better clue is how easy it crumbles in your hand compared to harder rocks. Color isnt reliable either because it changes when wet. So relying just on texture and look might lead you wrong. You really need to test if it breaks apart easily or leaves a sandy residue.

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drew_cooper7mo ago

True, I remember reading in a field guide that sandstone can be tricky smooth after long erosion, hiding its gritty nature. The author stressed checking for loose sand grains that rub off on your fingers, even on worn surfaces. @parkerw14 makes a good point about the crumble test being a safer bet than just eyeing it. From what I've seen, getting it damp really highlights if it's sandy or just a hard rock.

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piper_reed7mo ago

Wait but have you ever actually tried the crumble test on super hard sandstone? I chipped a tooth once trying to bite a small piece to test it! Some sandstone gets almost like concrete after years of pressure and won't crumble at all in your hand. That's why looking closely at the surface for any tiny pits or grain patterns is still super important before you start breaking things. Relying only on whether it falls apart could make you miss the harder types that are still sandstone.

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