Abstract: Glasses quenched from synthetic REE-carbonatite liquids in recent Tuttle bomb experiments require fast cooling rates. To study these glasses further, an internally-heated miniclave has been developed to increase quench rates and extend the operating P-T range of standard Tuttle bombs. The Haskel miniclave can achieve simultaneous P and T of up to 1200°C at 4 kbar for small diameter (1–2 mm) samples. Gas (Argon) pressure is supplied by a small intensifier unit and heating by an internal platinum-wound furnace. Because of the relatively small thermal mass, run temperatures can be reached within a few minutes and quench rates approach those of solid media apparatus.