Chapter 7 explores the question: how does rock formation and weathering help drive long-term climate change? This exploration is focused on the chemical processes of rock formation and weathering that release CO2 to the atmosphere or consume CO2 from the atmosphere. Weathering of silicate rocks uses atmospheric CO2, whereas weathering of organic-carbon-rich rock (e.g. coal) releases CO2. Feedbacks between atmospheric CO2 content, global climate state, and the rates of chemical weathering have created a self-balancing system that has stabilized Earth’s climate within a habitable range for ~the last 4 billion years. Tectonic uplift of unweathered rocks in a mountain range can disrupt this balance for timespans of a few million to a few tens of millions of years, driving the Earth from a Greenhouse state into an Icehouse state until the balance is restored.