Indiana Jones and the Cross of Coronado

The Cross of Coronado is an artifact that only appears in the first scenes of the 1989 George Lucas-produced and Steven Spielberg-directed blockbuster.

Far more importantly, the cross helps establish the mindsets of Father and Son in the early days and how their stories or motivations have changed over the next 30 years.

Indiana, an altruistic teen, looking out for the public good, believes that historical artifacts should be shared with the world and not in the hands of private collectors.  Indy later turns mercenary. So, by 1935, we find Jones willing to sell the ashes of Emperor Nurhaci to crime boss Lao Che for diamonds, eventually moving closer to wanting more than material objects to something somewhat spiritual, as he does in Raiders of the Lost Ark.  
It also shows how the Jones' succumb to their obsessions and tend to lose themselves to them.