The Diamonds are featured in Grand Theft Auto IV,The Lost and Damned and the recently revealed The Ballad of Gay Tony wherein they are involved in many scenarios also involving the Protagonists, Niko Bellic, Johnny Klebitz and Luis Fernando Lopez as well as many others. Detailed below are the many different scenarios which take place involving the diamonds and the different people that gain possession of them each time. The diamonds are the main purpose which led to the Impossible Trinity achievement.
Gay Tony and Luis Lopez are seen to attended a meeting with the ship's cook in order to obtain the diamonds. This deal however, was interrupted by Johnny Klebitz and several members of The Lost, on the orders of Ray Boccino.
Following the ambush, Johnny followed and killed Tony's boyfriend, Evan Moss and hid the diamonds within some garbage in Algonquin, in which the diamonds will be collected by Niko Bellic, Luca Silvestri, Joseph "Tuna" DiLeo and Johnny Spaz.
After the diamonds have been collected, Luca and his crew attempt to steal the diamonds for themselves and plan to move to Las Venturas, but are stopped and are killed by Niko.
Later on, again on the orders of Ray Boccino, Niko teams up with Johnny, though not for the first time, and attempts to sell the diamonds to Isaac Roth and Mori Green, members of the Jewish Mob. The deal is interrupted by Luis Lopez, who achieves his goal of stealing the diamonds and delivers them to Tony, who puts them in his safe. This deal is seen played out from three different perspectives; in Niko's point of view, Johnny's point of view and Luis' point of view.
Later on Niko and Packie kidnap Gracie Ancelotti on the orders of Gerald McReary in an attempt to trade her for the diamonds at a later stage. Gay Tony and Luis Lopez agree to strike a deal to trade the diamonds for the safe return of Gracie at an Oil Refinery on Charge Island after being threatened with death by Gracie's father should Gracie die or not be returned. Soon thereafter, the deal gets underway and seems to be going smoothly until Bulgarin appears, claiming that the diamonds were his before Gay Tony and Luis stole them. Following a shoot-out, one of Bulgarin's men grabs the diamonds and escapes up onto one of the metal walkways surrounding the refinery and holds them over the railings when he is cornered by Niko and Packie. Fearful for his life, no matter his decision, He decides to drop them over the railing into a passing garbage truck which is headed for the dump and with that he is promptly killed.
The last appearance the diamonds have are at the end of The Ballad Of Gay Tony's final mission, Departure Time. Luis meets Tony at the Monoglobe Monument after killing Rodislav Bulgarin on his plane. As he moves towards Tony, he "makes a scene" by bumping into a Jerry Kapowitz, knocking him over. He picks the old man up and walks away, not noticing the old man finding a puch on the ground. The old man reaches into the puch and pulls out a diamond, inspects it, puts it back in the bag and runs away laughing.
The last mention of the diamonds however happens when listening to Weazel News. It is said that a homeless man found them in a landfill, and were valued to be worth $2 million. 100 people attempt to obtain the diamonds before the mayor makes the decision to give them to the homeless man. The homeless man then speaks of his plan to sell the diamonds and use his money to open up a gun shop and a liquor store in Vice City.
Note the following missions are sorted in chronological order of the timeline.