The products you refer to are called cultured marble and cultured onyx. These happen to be two of the most popular finishes for bathroom vanity tops. Although the products are very similar in construction and equally durable, there are distinct differences in appearance.

Cultured marble is a material composed of a mixture of natural stone and polyester resin. It has a gel-coat finish, which provides a non-porous, stain-resistant surface. Each piece is unique, no two pieces are ever the same. Cultured marble products have a deeply-veined colorization throughout the substance, not merely on the exterior, which results in the appearance of real marble.

Cultured onyx also is made of natural stone and polyester resin with a gel-coat finish. However, onyx products have a radiant translucence, giving it depth, which is produced by superior