diamonds have a real intrinsic value other than "looking pretty", with mass-produced nanodiamonds helping to cure cancers.

Certain chemicals can greatly reduce the risk of lingering cells restarting all the cellular trouble after a tumor has been removed.  The problem is that getting those drugs into the system can either result in flooding the entire body with the agent, with all manner of unwanted effects, or using site-specific implanted patches which give up their contents all too quickly.

Unless they're made of nanodiamonds.  Thanks to their large biocompatible surfaces, the clusters of mini-gems can hold large reserves of many different kinds of agents which are slowly released over a period of months.

researchers at MIT are also working on using gold as a cancerbuster.