Review on 18 Pounds of Natural Polished Decorative Gravel - Pebbles Aquarium Gravel River Rock - Mixed Color Fish Tank Stones - Garden Ornamental River Pebbles Rocks - Polished Gravel for Landscaping (Multicolor) by Mike Carter

I was very happy with these for my purposes - arrived quickly, seems like a good price. The rocks look very nice and smooth. I only use them to decorate houseplants. If you are wondering how much 18 pounds of these stones weigh, I would estimate them to be the size of a shoebox. There was nothing on the packaging about suitability for aquariums, so I personally would not dare to use it in this way without further research.