Grospydites are a rare variety of eclogites composed of gros sular– py roxene – di sthene (kyanite) occurring only in a few kimberlite pipes worldwide. The pressures, temperatures and redox conditions of formation for grospydites have been poorly investigated, even though such parameters are needed to better understand their origin and the scarcity of elemental carbon (graphite/diamond), a common feature of these rocks. In thi...