Charcoal Diamond

Black's entry in the five-card Diamond cycle, the colored mana rocks Wizards printed once it had decided the Moxen were a mistake it would never repeat. The whole design argument lives in the enters-tapped clause: the rock comes online a full turn behind, so it can never chain into the explosive early acceleration that made the original Moxen unprintable. That single delay is the line between this generation of rocks and the broken artifacts they descend from. What the cycle traded speed for was durability. Casting it costs no colored mana, it dodges the removal aimed at the dual lands and creatures that produced black around it, and it makes its mana regardless of board state. The Diamonds taught a lesson Wizards has leaned on ever since: ramp does not have to be efficient to earn a slot. Two mana for a single colored source every turn is a losing rate on raw tempo, but it converts a generic artifact slot into fixing that is reliable, repeatable, and hard to interact with. That math has aged into near-irrelevance as faster untapped rocks took over the role, yet the cycle remains the cleanest illustration of how acceleration got priced after the Power Nine were quietly retired from the design vocabulary.