【Size & Weight】Black gravel size is about 3/8 inch. Total weight of a bag: 5 pounds. Our black gravels are unpolished and it'll be some powder on surface. It is a normal phenomenon 【Black Rocks】FANTIAN black rocks are natural with no polish or coating and no added fillers, dyes, oils, or substances. The color won't fade away through time and it is completely safe to use around fish tanks and children 【Black Stones】FANTIAN black pebbles are perfect for home decor projects, such as potted plants, vases,succulents, display glass jars, glass hurricane candle holders, cactus, bamboo plants,rock gardens, yard, paving the way and more 【Instructions】Our gravel is mechanically processed and the stone some powder on surface, which is normal. Before you use it for the first time, please make sure to wash it with water 2-3 times until its surface is clean and smooth 【After-sales Service】If you are not satisfied for any reason with our stones, simply contact us, we will find a satisfactory solution for you In the process of hundreds of millions of years of evolution, the pebbles have withstood the motion of waves, and the collision and friction of the gravel finally reached your hand. It is natural and non-toxic. Different shapes, patterns and colors make the pebbles unique. This is Artwork of nature