Okay, what you currently have is just an object with an associated effect. But there are already issues with the article.
After being around humans for a prolonged period of time
How long is this "prolonged period"? Also, since the procedures mentioned distance as a parameter, is the range involved relevant?
After an estimated 2 hours the blood will crystalize increasing the radius of the gem.
You do know that gemstones and blood are composed of either different materials. If what you wrote happened, the gem will not grow in size. Instead, it will just be a layer of blood coating it.
But onto bigger issues, SCPs are not just a bland description of objects that are weird. We have moved on from that stage years ago. You would need to think deeply about this object and consider how this SCP fit in the world of your fictional setting. How people responded to it, what it meant to a particular person or group… Since you have done so little with the base idea, it can just as easily make it or flop.
