I’m completely ignorant when it comes to meteorites, rocks and gems, my hobby is actually saltwater fish tanks and collecting corals. For new aquariums we sometimes use dry harvested from land ancient reef rock made up of calcium carbonate limestone. This rock comes from ancient reef when the Florida landmass was formed, you can sometimes see fragments of shells in these rocks.
I happened to get a piece which has a dark colored rock or metal embedded in it. I realized it was in there about a week after putting it inside my newly filled aquarium and I got nervous because most heavy metals in the water will kill corals. I called the place I bought the calcium carbonate limestone rocks from and also another reputable vendor who have both gone through tons and tons of these rocks but never seen anything like this before.
Typically the rocks are just whiteish porous limestone. I posted a pic in one of the fish forums I’m part of and someone said maybe it’s a meteorite that hit the ancient reef, which never crossed my mind. My mind tends to go to bad things, like uranium, which I see in google can be in limestone sometimes. Again, I’m completely ignorant and have no idea what this could be.
Anybody have any idea what this is or how to find out? The surface area is maybe the size of a dime. One picture shows the entire limestone rock in my aquarium, with the small piece I’m questioning towards the top. The other pics that are actually clear were taken in the sunlight when I pulled the rock out and it’s still wet.