Custard Grit dates back to the mid 19th century when it was originally discovered by the inventor of Bird's Powdered Custard. He realised that a poorly mixed bowl of Custard possessed incredible properties of strength and dryness (See BrickTop ).
Since then CustardGrit has been used in the building trade as a replacement for cement in some places. It was also used in factories as an industrial abrasive, useful for sandblasting or mining. It was famously used to coat the outside of the first manned mission Vostok 1 to space due to it's high heat resistance. Said YuriGagarin at the time: "Eto ochen' gryazno" which roughly translates to "It's pretty dry".
Unfortunately however modern materials have seen the almost complete phasing out of CustardGrit as an industrial material.
YuriGagarin
CustardGritRefinery