Sometimes, a specimen is so small, it's hard to know how to create form in a bold way that is really informative. The image below is a model carved by Frank Merrem. Easily available materials (ranging from paper clay to Sculpy to Styrofoam) can be employed to make a large, easy to see specimen, which may then be lit to effectively reveal form..
Here's the finished color sketch.
Note the scale bar to the right, which tells you how truly tiny the specimen is. And yet, Frank developed an understanding of the 3-dimensionality of his subject using his model. Frank is an experienced photographer, and his understanding of gray scale informs the photo. Sometimes, a black and white rendering of a photo can be a powerful aide to understanding form also.