I found this rock at my friend's summer cottage in Finland. I have never seen a rock like this in my life. It resembles a lava stone, but Finland isn't a volcanic country. I am no expert in geology can someone help?
Update: So I once again visited my friends summer cottage and I remembered that I was advised to take a sample from the stone I found. I hammered too little pieces off the rock. It's completely dark from the outside but from the inside it's like a normal stone. I also rubbed it on to unglazed porcelain and it left a dark black streak like a piece of coal. So if you have any ideas what kind of stone this might be, give me your opinions?
Here are some pictures: