: Add one mana of any color.Mox Diamond trades a land card in hand for immediate, flexible acceleration. It costs zero mana and taps for any color, but keeping it on the battlefield requires discarding a land as it enters. Decks that can recover lands or make unusually good use of an early extra mana are best positioned to turn that exchange into an advantage.
Life from the Loam can return the discarded land to your hand, while Crucible of Worlds lets you play it from the graveyard using an available land play. Exploration complements that plan by allowing an additional land play each turn. Together, these cards help a lands deck use the graveyard as a resource while Diamond supplies colored mana for its early setup spells.
The extra mana can also bring a commander or card-advantage engine online ahead of schedule. In a multicolor opening hand, Diamond’s fixing may be as useful as its acceleration, particularly when the lands you intend to play include colorless utility lands. Keep track of the land you discard, since spending your only suitable land can leave the rest of the hand awkward.
The discard is part of a replacement effect, not an enter-the-battlefield trigger. You cannot let Diamond enter, tap it for mana, and then decline to discard. Without the land discard, it goes to the graveyard instead of entering. That makes hand selection important: Diamond rewards sufficient land density and a plan for recovering the card investment, rather than serving as a free resource in every opening hand.
