So I understand that this is going to be a very difficult thing to properly do but I am looking to create a vessel for growing crystals. I am not looking to build a Verneuil furnace bit rather a container to heat and pressurise to mimic where they naturally grow. My current thoughts for heating are either a tungsten coil, heated in an argon pressurised container, at about 1000 Kelvin and 300 psi or a Browning generator superheating a container in an oxygen pressurised container. I will either be melting flux which will require a far lower pressure or superheating water to supersaturate it, requiring a lower temperature and the same pressure. What ideas do you have to make a vessel like this?