In this invited review, we summarize the main results of ongoing research on “in situ” carbon mineralization in ultramafic rocks, including outcrop studies in Oman (e.g., [1, 2]), investigation of carbon mass transfer in subduction zones from the Oman Drilling Project (e.g., [3-7]), laboratory investigations (e.g., [8-12]) and numerical modeling (e.g., [13-17]) of the pressure of crystallization and reaction-driven cracking, and assessment of the rate, cost and capacity of various proposed methods for engineered carbon mineralization [18, 19].