What did the Limestone say to the Geologist?

The joke “What did the limestone say to the geologist? Don’t take me for granite!” is a play on words, mixing geology with a common phrase. Limestone and granite are both types of rocks that geologists study. The humor comes from the phrase “Don’t take me for granted.” This phrase usually means “don’t underestimate me” or “don’t fail to appreciate me.” The joke replaces “granted” with “granite,” which sounds similar. So, the limestone is making a pun, telling the geologist not to confuse it with granite, but also playing on the phrase about being appreciated or recognized for what it truly is.