DeBeers controls the diamond market and apparently has decided there is a glut of grey and orange diamonds!
The jewelery company is showing these unusual stones hoping they will capture enough market share to continue to keep diamonds as the luxury standard for jewelry. DeBeers is known for manipulating the demand for stones. They will decide that smaller stones need more demand and will withhold larger stones. Then when the market has shown the demand slowing, they release the larger stones - thus making your small stones unfashionable.