黑剛玉砂(又名底鋁剛玉砂，鐵砂粉)是一種新型拋光材料.以三水型和一水型鋁樊土為原料經電弧高溫冶煉冷卻加工而成.黑剛玉磨料基本粒集中，切削力強，任性大，剛柔相濟，耐磨性好，工效高.主要用于不銹鋼，金屬制品，光學玻璃，竹木制品的拋光和噴砂，又是制造樹脂砂輪，切割片，砂布的新穎磨料.

Black aluminum oxidde abrsasives is a new type abrasive material for polishing various metal works.It is electrical fused in an arc furnace from aluminum oxide as raw material.Black aluminum oxide abrasive is featured with high hardness.strong tanacity，good self-sharpening，better cohesiseness，higher durability，less heat generated in grinding and giving the metal works high finish，less power weakened in grinding.It is mostly used in grinding and polishing stainless steel，metal works，optical glass，bamboo or articles.and it is also the new grinding material of producing colophony grinding wheels， slice，and emery cloth.