Yes to human made. You notice the hole has little marks around it? And it is made of slate, which is metamorphic rock so that means a naturally occurring mollusk drill would not have survived the transition from sedimentary to methamorphic.
You can tell that the hole was made with a stone drill because it is beveled on one side and not the other. The beveled side would be the entry point and it is beveled because of the way the drill was tapered.
That doesn't look like slate to me. Slate, at least the slate around here, is more slick looking. That looks like an igneous rock of some sort. Regardless, it is for sure man made and maybe a simple pendant. Gary