I don't exactly know

[Abbystarkweather]

so I found what I think is an arrowhead in Lake winnipesaukee, New Hampshire, about 5 or 6 years ago when I was probably ten or nine years old. I was just swimming in the shallow water and found it turned up in the sand. It's flat on the bottom and the rock has a weird smell. As most like if you grind two rocks together but different. Most the edges are dull like it was dragged in the sand. It looks pretty old. I couldn't find anything like it researching, it's unlike the obsidian or carved ones. It's more of a matte stone.

[pkfrey]

I believe you found a chunk of argillite. The odor you mentioned is what I posted about in another post. It's a musty, groundy, sometimes sulpher smell. It happens when argillite gets wet, or is ground against another stone. not an arrowhead or artifact, but the material was used for artifacts

[Abbystarkweather]

I think it's strange that there are completely flat surfaces. That usually doesn't occur in nature. It also doesn't look like it just casually broke off a piece of stone. There are clear, sharp edges that purposely shape a point. Also triangular indents on both sides.

[BabaORiley]

Welcome Abby. New Hampshire is a ways from my realm here in N'Eastern Illinois. It looks like the material is granite of some kind. As far as being man made I really don't know, I'm not going to rule it out without better views. The third pic shows some possible flake marks. If you can show some other angles in outdoor light that will help a lot. Also there are a bunch of NorEasters here that can probably nail it down for ya...

[BabaORiley]

Well there ya have it...lol...I walked away before posting to let the dog in and ya have an answer...

[-=METACOM=-]

Looks like a rock from the pictures...

[SDhunter]

Welcome Abby. Sorry it's not an artifact. ☹️