What is it?
Found a mysterious fossil or a strange rock formation? Not sure if something is man-made or a geological phenomenon? Please try to include a picture with your question, and we will try and identify it.
If you have a rock, fossil or mineral that you need help identifying, you can also try the Natural History Museum's identification forum. Post your questions and photos and receive help from experts from the Museum and the NaturePlus community: www.nhm.ac.uk/natureplus/community/identification/fossils-rocks.
Here are the questions you have sent in that we have answered. Click on the questions below to read the explanation given by one of our geologists.
Please note, Ask a Geologist is not currently accepting new questions - we apologise for the inconvenience!