The The Diamond Heist Add-on for PAYDAY 2 has 12 achievements.
In The Diamond job, complete the heist without triggering the alarm. Unlocks "The Cursed One" mask, "Sand" material and "Hieroglyphs" pattern.
In The Diamond job, steal the Diamond and escape in under 10 minutes. Unlocks the "Pazuzu" mask, "Diamond" material and "Horus" pattern.
In The Diamond job, complete the heist while you and your four man crew are wearing one different "Diamond Heist" mask each on the OVERKILL difficulty or above.
In The Diamond job, complete the heist, diamond puzzle and steal the Diamond after the alarm has been triggered on the OVERKILL difficulty or above. Unlocks the "Anubis" mask, "Mummy Bandages" material and "Hawk Helm" pattern.
Complete The Diamond job on the Normal difficulty or above.
Complete The Diamond job on the Hard difficulty or above.
Complete The Diamond job on the Very Hard difficulty or above.
Complete The Diamond job on the OVERKILL difficulty or above.
Complete The Diamond job on the Death Wish difficulty or above.
In The Diamond job, secure 10 bags of additional loot. Unlocks the "Medusa" mask, "Rusting Metal" material and "Runes" pattern.
Complete The Diamond job on the Mayhem difficulty or above.
Complete The Diamond job on the Death Sentence difficulty with the One Down mechanic activated.