otherI found this rock on the beach of a freshwater lake in the Finger Lakes region of New York state and am interested in knowing more about it.

It is about 2" tall and 2" wide at widest point. Weighs 14.6 ounces. Hardness scale is 2.5 with fingernail. First time doing specific gravity but I believe it's about a 2. Scratch test is a light brown. Kind of in a cylinder shape that is tapered but kind of flat on top and bottom. Looks kind of side[![toplayered and holey, I would say luster is dull, not smooth but not really rough.

side view top view bottom view another angle

  • $\begingroup$ Looks like an impure sandstone, maybe an arkose or something like that $\endgroup$ – Gimelist Mar 3 '18 at 7:46
  • $\begingroup$ Please read this meta post for rock identification posts. $\endgroup$ – Eevee Mar 3 '18 at 13:24
  • $\begingroup$ Well, you've been busy ;-) $\endgroup$ – Jan Doggen Apr 1 '18 at 12:42

It looks like sandstone. It looks grainy. The reddish parts are oxidized (rust) and called arkose sandstone. The black is oxidized titanium. I lived in Virginia and you would see similar rocks in the mountains there.

I checked the bedrock geology map to make sure sedimentary rocks outcrop in the area you mentioned and they do. http://www.nysm.nysed.gov/common/nysm/files/surf_fingerlakes.jpg

A little farther east and you get into metamorphic rocks which have a crystalline texture (harder and less granular). The hardness measurement is usually used to describe a mineral not a rock. Hardness testing a clastic rock such as this explains more about its cementation and grains than the minerals that make it up.


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