A heel is the bottom, back part of a shoe or boot that provides elevation. The styling and construction of a heel may vary (i.e., stacked, stilletto, spiked, sculptured, kitten).
About Nubuck:
This is a grain leather that has been slightly brushed on the surface to create a very fine velvet-like appearance. The texture of nubuck is finer than suede.
About Sandals:
An open type of shoe that consists of a sole fastened by straps to the foot. Types of sandals include espadrilles, flip-flops, strappy sandals, and thong sandals.