Calci-sand
From UroWiki
Calci-sand (also known as Calcium sand) is a calcium-based commercial substrate produced by T-Rex, which is believed to be responsible for the deaths of many uromastyx, bearded dragons, geckos, and similar creatures due to internal build-up and impaction.
Common misconception
According to HerpCentre.com, "The average enthusiast that strolls into their local petstore is often met with an employee who tries to help them choose a suitable substrate for their reptile. In many instances, they lead the enthusiast directly to the calcium sand they sell, and go on to explain how it is 100% digestible and safe for use. The employee and customer know this must be true, because it is printed directly on the bag."
