Partially worked Obsidian Knife

A good friend of mine found this on his land in Modoc County, CA. He gave it to me a few months ago, and i promptly broke it. i already feel pretty ashamed about it, so let's not talk about that, please. I tried posting it on an arrowhead site on FB, but it was rejected by a moderator who said it is just natural stone. I don't believe it is natural for a second! It's obviously been deliberately stuck in quite a few spots. It's very thin and even has sharp edges, but the point appears to be broken off too. I'd love to hear from some artifact experts! Thank you.