"Soft pastels are created by combining the pigment with water and a form of artificial binder. They are very dry, crumble easily and have a feel that is comparable to a stick of chalk. Oil pastels are slightly more durable than soft pastels and will not crumble as easily."
I was first introduced to oil pastels when I was a student at various art institutions. Although, I have not created many paintings using oil pastels, I still enjoy using oil pastels as one of the materials that I implement for my collage art.