Dense hydrated Mg-silicates in diamond: Implications for transport of HO into the mantle.

Water in Earth's upper mantle is a minor and yet critically important component that dictates mantle properties such as strength and melting behavior. Minerals with stoichiometric water, such as those of the humite group, are important yet poorly characterized potential reservoirs for volatiles in the upper mantle. Here, we report observation of hydroxyl members of the humite group as inclusions in mantle-derived diamond.