Metallica's The Black Album received a 2× Diamond certification from the RIAA for shipping 20 million copies in the United States.
The Recording Industry Association of America awards a Diamond certification for ten million units, so a double-Diamond award represents 20 million. The album reached that milestone decades after its 1991 release, reflecting unusually durable sales across CDs, downloads, and other eligible formats.
The record had already become one of the best-selling albums of the SoundScan era. It was also described as the first album tracked by SoundScan to pass major sales milestones such as 16 million US copies. Those sales figures and certification totals are related but not identical: certifications measure units shipped or certified under RIAA rules, while sales reports may describe units sold.
The album's worldwide impact was even larger. It has sold more than 30 million copies globally and remains Metallica's best-selling release. The certification therefore captures only its US performance, not the full international total.