What are the perfect alternatives to natural sand for the production of machine-made sand?

What are the ideal substitutes for natural sand in the creation of artificial sand?
As the demand for sand continues to rise, the depletion of natural sand resources has become a pressing issue. This has led to the exploration of alternative materials for the production of machine-made sand.
What are the most suitable options for replacing natural sand in the manufacturing process? This question has sparked a great deal of research and development in the construction industry. By identifying and utilizing effective alternatives, we can reduce our reliance on natural sand and preserve our planet's resources.