i calculate for the pillar their real weight doing pixel measurement and taking average colonist head size i end up with a pillar of 20cmØ and 70cm of length (for our size it's around a 50cl bottle) it give me a pillar of around 44kg (rounded up) for the granite and the marble is around the same weight

and if we take the 18kg you gave to the pillar and convert it in a pillar mass we have for the closest a pillar of 12cmØ and 80cm of length

🤓 so just know you could theoretically use this pillar as a weapon 🤓