Construction materials. No building shall be erected in any commercial district, whether main or accessory, which has any part of its exposed exterior wall surface composed of concrete block or cinder block, except as herein set forth. Exposed exterior surfaces on any such building shall be composed of the following materials only, unless additional materials are reviewed and approved by the Borough's Planning Commission to be of equal or superior quality and aesthetic character when used under the circumstances proposed: brick, stone, glass, marble, wood (only as approved by the Planning Commission), metal (only as approved by the Planning Commission) and architecturally faced concrete block (only as approved by the Planning Commission).