Seiryu Mini Stones areblueish grey in color with contrasting calcilte veins and sharp jagged edges, they are one of the most popular hardscape stones used in aquarium aquascape The minimum order for Seiryu stones is 4 lbs (which may be as few as 1-2 stones as these stones are rather heavy in weight) The stones we ship to you will closely match your ordered weight, but may not be exact because its a natural object. We will aim to target your weight, but may end up slightly over or slightly under. GLA will select the stones up to your ordered weight. We will aim to provide a mixture of sizes/variety. The listing picture above is for example only, these will not be the stones you receive in the shipment. 4 lbs may be appropriate for a smaller tank size, for larger tanks please consider ordering 10lbs+ These stones will alter aquarium pH depending on quantity, aquascape, and tank conditions. They are safe for shrimp tanks.