What is the most precious gem on earth?

I'm curious, what is the most valuable gemstone known to mankind? Is it a diamond, with its unparalleled brilliance and rarity? Or perhaps it's a rare emerald, with its captivating green hue? Or could it be a sapphire, renowned for its deep blue coloration? The question of which gemstone reigns supreme in terms of value and rarity has intrigued collectors and enthusiasts for centuries. What do you think sets this particular gem apart from the rest, making it the most precious on earth?