evidence: A video demonstrating waterjet cutting technology has been widely shared on social media, claiming that with significant pressure applied to water and forced through a tiny nozzle, it can slice through even the hardest materials, such as rocks, bulletproof glass, iron, and diamonds. Let’s examine the accuracy of the claim made in this post. [...] Fact: While pure waterjet cutting can be used to cut softer materials, abrasive waterjet cutting is required to cut through harder substances such as metals and ceramics. This is because abrasive particles like garnet or aluminium oxide are added to the high-pressure water stream, which increases the cutting force and allows for effective cutting of hard materials. Therefore, the claim made in the post that water alone can cut through the hardest materials, including rocks, metals, bulletproof glass, and diamonds, is MISLEADING. [...] To sum it up, while pure water cutting can effectively cut soft materials, abrasive waterjet cutting is necessary to cut through harder substances like metals. Abrasive particles, such as garnet or aluminium oxide, are added to the high-pressure water stream to enhance cutting force and enable the waterjet to effectively cut through hard materials.