[@Kronshi]
See, that's where I disagree. At least partially. We only have one example of gems cracking shown and that was when Amethyst fell off the cliff, assuming she's not some super dense being she would have fell about the same speed as a person give or take. And sure, she landed on a rock but that force is nothing near the force of a bullet careening through the air. Then we have the poofing of Pearl, sure you could make the case that the Holo-Pearl was super strong and thus could push the sword through Pearl, but even then the right ammunition would do. The only thing I see that would be able to shrug off small arms fire would big fusions like Sugilite and Sardonyx.