Rock dust is either used as a clay substitute, or a sand substitute to make pottery. Stronger, and comparatively light-weight ferrocement containers can also be made, and used for water storage or other purposes.
Urbanization has removed green spaces, so there is a recent trend to grow plants in terrace gardens in containers. Plastic bags do not transpire, and start breaking in less than 6 months in sunlight. Plastic containers last for several years, but they suffer similar drawback, in that they do not allow transpiration. The roots and soil heat up in hot weather. Plastic may be good enough, in growing plants under shade net, with reduced sunlight.
The best containers are terracotta pots. They keep the soil cool, let earthworms flourish, and generally are more suitable for plants. Fine rock dust from washed M-sand, can be used as an additive to clay. This will reduce demand for clay mined from lakes. Rock dust may make for stronger pots, so we can make thinner and bigger pots.
Using rock dust as aggregate, with slightly higher proportion of cement, gives us a much stronger product. So cement pottery for plants, or cement containers for water, can be made with rock dust.
Cement containers are less porous, and do not transpire as much as terracotta. Lime, instead of cement will make more porous pots, and will be better for plants.
Ferrocement containers can be made thinner, 10mm or less in thickness. The steel mesh reinforcement makes it stronger. Water containers holding more than a thousand liters of water can have walls less than 15mm thick .