Mox Diamond — ruling 1

If you don't discard a land card, Mox Diamond never enters. It won't trigger abilities that look for something entering, and you won't get the opportunity to tap it for mana.

Mox Diamond : règles, fonctionnement et interactions (MTG)

Mox Diamond is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

If this artifact would enter, you may discard a land card instead. If you do, put this artifact onto the battlefield. If you don't, put it into its owner's graveyard. : Add one mana of any color.

Complete guide

Mox Diamond is a powerful piece of fast mana that accelerates your game plan at the cost of a resource. Unlike many artifacts, it requires a specific commitment before it ever touches the battlefield. This guide explains how its replacement effect works and how to use it effectively.

Understanding the Replacement Effect

Mox Diamond features a static ability that creates a replacement effect. Unlike a triggered ability that uses the stack (starting with 'When' or 'Whenever'), this happens exactly as the card would enter the battlefield. You must choose to discard a land card or send the Diamond directly to the graveyard as it attempts to resolve.

Step-by-Step Resolution

When you cast Mox Diamond and it resolves, you reach a decision point. First, you decide whether to discard a land card from your hand. If you do, the Diamond enters the battlefield and is ready to be tapped for mana. If you choose not to discard a land, or if you have no land cards in hand, the Diamond moves from the stack to the graveyard without ever being on the battlefield.

Common Mistakes

A frequent error is assuming you can tap Mox Diamond for mana in response to its discard requirement. Because this is a replacement effect and not a trigger, the Diamond is not on the battlefield when you make the choice. If you don't discard the land, it never enters, meaning it won't trigger cards that care about artifacts entering the battlefield.

When to Play It

Mox Diamond is best played in the very early turns to jump ahead of the mana curve. It is particularly strong in decks that can afford to lose a land card in exchange for immediate color fixing and explosive starts. Since it costs zero mana, it allows for powerful follow-up plays on turn one.

Interaction examples

Explosive Turn One Start

Sol Ring

You play a land, then cast Mox Diamond. As it resolves, you discard a second land card from your hand so it enters the battlefield. You can then tap Mox Diamond for a generic mana to cast Sol Ring, ending your first turn with four available mana.

Utility and Equipment

Skullclamp

After discarding a land to ensure Mox Diamond enters the battlefield, you can immediately tap it for a single mana of any color. This mana can be used to cast Skullclamp or pay its equip cost, turning your fast mana into card-draw utility.

Guide written with AI from the official text and rulings. Official English text prevails.

How it works : Mox Diamond

Original English text — Wizards of the Coast / Scryfall

#1May 1, 2008· Wizards of the Coast
If you don't discard a land card, Mox Diamond never enters. It won't trigger abilities that look for something entering, and you won't get the opportunity to tap it for mana.
No other card is named in this ruling.