What is the #1 rarest GEM?

Could you please elaborate on what you mean by the "#1 rarest GEM"? Are you referring to a specific type of gemstone that is considered to be the rarest in the world? Or are you asking about a rare digital asset or cryptocurrency that is often referred to as a "gem"? If it's the latter, it's important to note that the value and rarity of digital assets can fluctuate greatly and are often subjective. However, if you're looking for a rare gemstone, some of the most sought-after and valuable include the red diamond, the blue diamond, and the pink diamond. But ultimately, the answer to your question will depend on the specific criteria you're using to determine rarity.