So I was out doing preliminary scouting for my second favorite hobby - mineral and rock collection - when I found a rock that looks SUPER deep purple (on the verge of black) while in the sun, however for these pictures it just looks black. It's heavier than it should be for the size, about as big as a chicken, and it's mostly smooth with some pitting. When I tried to smash it with a 2 pound ball peen hammer, it sparks like I'm striking flint on steel and smells like spent shotgun cartridges. The only pieces I could get off it was instant dust plus the small chip pictured below. There is absolutely zero luster, but it does sparkle. It has exactly zero magnetic qualities, and any discoloration you see in the pics is from dirt, I see no observable color striations.

Any ideas?

https://imgur.com/gallery/QnXnFMu
https://imgur.com/gallery/bOi5hXb
https://imgur.com/gallery/J47dUCu

This post was edited by Disturbed*One on Feb 29 2020 11:25pm

My first guess would be chert. Although chert normally isn't black, but could be a purple color due to the makeup of the minerals of the rock. It breaks into pieces like the flake picture you showed. It could also be flint since you mentioned that and that would be explain the black color. Flint is just a type of chert.

whats the general location of where you found it?

I'm located in Chico, CA and that was found on the banks of the Feather River in Oroville, CA

Could be quartzite as well just bc it appears massive and hard. Quartzite and chert have pretty obvious textures on a freshly broken surface. That area is mapped as having marine deposits which could include chert, but it being a river rock gives it a lack of a definitive source. There are volcanics mapped to the east, but they appear to be more felsic in composition, which would typically lend to a lighter color and small crystals. Looking at other rocks in the area would probably help to identify your rock.

Download the app rockd and you can see how your particular location is mapped. You can also see formations in the area, which you could research a little to get a better idea of the compositions of typical rockses

This post was edited by JadeBlade23 on Mar 15 2020 11:20pm