Special thanks to Yelena of June Daisies for guessing correctly. It is food coloring in oil.
Here's a quick how to: Fill a clear glass dish a little over half full with water. Drop oil into the water (canola oil here). Then drop food color into the water. The first abstract was as the color hit the water and spread. The others are playing with the water flow. The important part is you need to have your camera directly above. I lit this from both sides and used a white background underneath the dish. Give it try and be sure to send me your pictures. I'd love to see them.
Hope you all had a lovely weekend!