Disclaimer: my hatred of geologists is purely theatrical, but if I did have to kill one for some reason, it would be very easy.
I’d brandish my obsidian knife at them and they’d be compelled to approach. “That’s very cool,” they’d say, confident in their superior strength and endurance from all the rocks they carry around at all times. They’d shower me with very interesting facts about obsidian and hover just out of range of the cutting edge, waiting for me to exhaust myself. “But as it is volcanic glass, it’s very fragile, you see, and isn’t well-suited for use as a weap—” and then I’d hit them with the wooden baseball bat in my other hand, which they would not have noticed because geologists can only see rocks and minerals.

𝓓𝓮𝓪𝓻 [streamer name] , 𝓘 𝓻𝓮𝓰𝓻𝓮𝓽𝓯𝓾𝓵𝓵𝔂 𝔀𝓲𝓵𝓵 𝓫𝓮 𝓻𝓮𝓼𝓲𝓰𝓷𝓲𝓷𝓰 𝓯𝓻𝓸𝓶 𝓫𝓮𝓲𝓷𝓰 𝓪 𝓫𝓮𝓵𝓲𝓮𝓿𝓮𝓻 𝓪𝓷𝓭 𝔀𝓲𝓵𝓵 𝓫𝓮 𝓳𝓸𝓲𝓷𝓲𝓷𝓰 𝓽𝓱𝓮 𝓭𝓸𝓾𝓫𝓽𝓮𝓻𝓼 𝓲𝓷 𝓭𝓸𝓾𝓫𝓽𝓲𝓷𝓰 𝔂𝓸𝓾𝓻 𝓪𝓫𝓲𝓵𝓲𝓽𝓲𝓮𝓼.