Variants

Variant(s) is the term used to describe when one item has multiple graphic sprites.
These variants are purely cosmetic, the items will still merge into a single stack. When split into multiple stacks (by tapping the original) or throwing the item, there is a chance that it will change to another variant. But once again, it's still the same item, and will merge back into the stack.

A good example is the Apple which is seen in both red and green.