Green Seaweed Fossil (IMAGE) Virginia Tech Caption A photo of a green seaweed fossil dating back 1 billion years. The image was captured using a microscope as the fossil itself is 2 millimeters long, roughly the size of a flea. The dark color of this fossil was created by adding a drop of mineral oil to the rock in which it's embedded, to create contrast. Credit Virginia Tech Usage Restrictions Credit Virginia Tech License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.