Egyptologists have suggested that the black rock was popular for funerary uses because it symbolized the dark, life-giving Nile mud.
The first, in 1971, "A Horse of Mud," focused on illiterate women earning a pittance shaping bricks from Nile mud.
The star hung resplendent on Nicholas's grubby shirt-front, heavily stained with sweat and dust and Nile mud.
Thus I would run needles steeped in Nile mud beneath my finger-nails, so that the sores festering might produce a sickening agony.
The grave chamber held some bones of a man and hundreds of offering vessels were found in the stairway which was blocked with masonry of Nile mud and stones.
It struck with the sound of a boulder dropped from a height into a bed of thick Nile mud, and half the length of the shaft was driven through his chest.
Everyone stared down at him in horror, appalled by the spectacle of Royal Egypt sitting waist deep in sticky black Nile mud with a startled expression on his face.
Clothes, armor and skin were plastered with dried Nile mud; they were black men, but for their light angry eyes.
His father was the creator god Khnum, who made him on his potter's wheel of Nile mud at the moment of creation of Earth.
Then into Nile mud with it!