Zirconia are used to simulate an image of a diamond, meaning they're fake. Being that "Gem-Knight Zirconia" is a fake diamond, it is an imperefect version of "Gem-Knight Master Diamond", reflected by its stats.
This card is tied with "Gem-Knight Master Diamond" for having the highest total base ATK and DEF of any "Gem-Knight" monster.
Unlike other "Gem-Knight" Fusions, this card does not hold a weapon, having two large fists instead. This follows the pattern of "Gem-Knight" Fusions having weapons that relate to their effects: this card has no effect, so it has no weapon.
This is the first non-Effect Fusion Monster to not have any specifically named Fusion Materials.