These robust cold-seal hydrothermal pressure vessels are the primary experimental apparatus in the lab, designed for simulating geological conditions from the Earth's surface to its deep interior. The facility includes both a custom-built, manually-operated system with two vessels capable of reaching 400 MPa (4 kbar) at up to 650°C, and an automated 4-vessel LECO system that can operate up to 200 MPa (2 kbar) and temperatures up to 950°C. Both systems utilize water as the pressure medium and are constructed from durable Rene 41 Ni-alloy. Experiments can range from minutes to months, with rapid quenching achieved by cooling the vessel with compressed air under isobaric conditions. These vessels are ideal for a wide range of applications including mineral synthesis, water-rock interaction studies, and element partitioning experiments, providing precise control over pressure and temperature for simulating various natural processes.