Revisiting the Rarity of Diamonds: New Research Challenges Old Beliefs.
New research suggests that diamonds may have always been rare, contrary to previous beliefs. The study focuses on the purple pyrope garnet, which is consistently found near and inside diamonds. The research uses a new model to suggest that these garnets form much deeper in the mantle than previously thought, at the same depths as diamonds. The study also suggests that the roots of continents were formed by the same mantle melting events that produced pyrope garnets. The rarity of diamonds is inferred from the fact that the particular composition associated with pyrope garnet is very rare, and has always been so, even on the early Earth.