I've grown crystals of aluminum phosphate, which, as far as I understand, is aluminum ammonium phosphate. I've seen excellent results with monoammonium phosphate. However, I only see it for sale in bags of a few pounds as a fertilizer and in tiny crystal kits at inflated prices.

You're right, monoammonium phosphate is easier to work with and produces excellent crystal clarity. If you're looking for laboratory grade material instead of fertilizer, consider using specialized suppliers. They offer smaller, purer batches for crystal growing without inflating prices.

Monomonium phosphate is really excellent for such experiments because it dissolves easily in water and quite beautifully crystallizing. It's best to buy pure mono ammonium phosphate and develop crystals themselves. In this way, you control the process, purity and the size of the crystal, and save money. It's important to keep glass -made substances and water clean, prepare the saturated solution carefully, and slowly cool it. This affects the quality of the crystal. Sometimes it helps to add a small seed crystal to ensure smooth and beautiful development.