A: According to BBC, an endoskeleton is a bone structure located in the interior of an animal, and an exoskeleton is a bone structure located on the exterior of an animal. Each type of skeleton has unique advantages and disadvantages in helping the animal survive.
Minerals made of only one element are called NATIVE minerals (i.e., silver, gold, mercury, copper). Minerals composed of compounds are simply referred to as minerals (i.e., quartz, which is made up on silicon and oxygen).
Confidence votes 10.3K. It depends on what the crystals are being made from. Ice is a crystal made up of water (hydrogen and oxygen) Quartz is a crystal made up of silica and oxygen Pyrite (fools gold) is a crystal made from iron and sulfur.ce is a crystal made up of water (hydrogen and oxygen) Quartz is a crystal made up of silica and oxygen Pyrite (fools gold) is a crystal made from iron and sulfur.