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.
𝓑𝓻𝓸𝓽𝓱𝓮𝓻 𝓘 𝓻𝓮𝓬𝓮𝓲𝓿𝓮𝓭 𝔂𝓸𝓾𝓻 𝓶𝓮𝓼𝓼𝓪𝓰𝓮 𝔀𝓮𝓵𝓵. 𝓘𝓽 𝓮𝔁𝓬𝓲𝓽𝓮𝓼 𝓶𝓮 𝓽𝓸 𝓲𝓷𝓯𝓸𝓻𝓶 𝔂𝓸𝓾 𝓪𝓫𝓸𝓾𝓽 𝓪 𝓬𝓸𝓬𝓴 𝓻𝓮𝓼𝓮𝓻𝓿𝓮, 𝓯𝓻𝓮𝓽 𝓷𝓸𝓽, 𝓬𝓸𝓬𝓴 𝔀𝓲𝓵𝓵 𝓫𝓮 𝓼𝓮𝓷𝓽 𝔂𝓸𝓾𝓻 𝔀𝓪𝔂 𝓼𝓸𝓸𝓷.