A high pressure magic angle spinning (MAS) NMR capability, compromising of a high pressure MAS rotor, a high pressure loading/reaction device for in situ sealing and re-opening of the valve of the high pressure MAS rotor, and a MAS probe with localized RF coil for background signal suppression, is reported. Use ceramics as the sample rotor cylinder, and plastics glued in a “smart way” at the both ends of the cylinder for high pressure seal, pressure exceeding 100 bars is achieved with minimal penetration loss of pressure during a period of 72 hours. As an example of application, in situ 13C MAS NMR studies of the reaction products and intermediates associated with geological carbon sequestration using a model mineral, i.e., forsterite (Mg2SiO4) reacted with supper critical CO2 and H2O at 50C are carried out and preliminary results are reported.