The mineral serpentine is the result of low-grade metamorphic reactions between ultramafic rocks and water. Given that the rocky envelopes of the terrestrial planets and moons are mainly ultramafic, and water is a common molecule, especially on the outside of these bodies, serpentine assumes a position of significance. The production of serpentine is associated with the existence of organic molecules on asteroids, and the origin of life. On the Earth, it is linked to magnetic anomalies on the sea floor, it lubricates subduction zones, and contributes in a major way to chemical recycling of water and other elements. It creates aquifers in regions short of surface water, and the reaction is proposed as a mechanism of carbon sequestration. In my research in the World Heritage listed Bay of Islands Ophiolite in Newfoundland, I have located springs of alkaline water using magnetic surveys, based on the assumption that local serpentinization produces magnetite. But does it?