The weight of 1m3 of slate varies depending on the specific type of slate and its density. On average, slate has a density of 2.7g/cm3, which means 1m3 (1000L) of it would weigh approximately 2700kg (5952 lbs). However, the weight can range from 2300kg (5070 lbs) to 3200kg (7055 lbs) depending on the type and quality of slate.