What makes a volleyball shoe a volleyball shoe, as opposed to a basketball shoe or a running shoe? The short answer is soles and weight.
Soles: The sole is at the heart of what makes a volleyball shoe a volleyball shoe. Most volleyball shoes have gum rubber soles. Gum rubber is the best material for soles because volleyball shoes are made for indoor court surfaces (usually wood) and because volleyball requires a lot of starting, stopping, and quick cuts. Gum rubber provides the best traction for the volleyball shoe on the very smooth wooden court surface. Other athletic shoes, such as running shoes, do not use gum rubber because they are designed either for outdoor use or for a greater variety of surfaces. Gum rubber does not look like the rubber used on most athletic shoes. Rather than being solid in appearance, gum rubber is semi-transparent (you can almost see through it). If the soles on the volleyball shoes you just received DO NOT match your mental picture of gum rubber, it is because today's gum rubber is dyed to match the shoe. Manufacturers also mix other types of rubber with the gum rubber in the sole to improve traction and mobility.
Weight: Weight is the other feature that makes a volleyball shoe a volleyball shoe. Almost all the top volleyball shoes are lightweight. Some volleyball shoes may be a bit heavier; however, these usually are the less expensive models.