Thinking about buying some Walnuts import from China? Think again. The country famous for selling counterfeit goods and toxic toys is at it again. This time with fake walnuts filled with rocks.

The sale of rock walnuts is apparently so prevalent that there is a video on YouTube titled, “How to spot a fake walnut and the return of making fake walnuts.”

According to the video, a fake walnut is dry and won’t make a sound when cracked.