After the Angel of Death collected the different sands from the earth, the sand was made into clay. It was then left until it became firm. Thereafter, Allah Ta‘ala fashioned the form of Nabi Aadam (‘alaihis salaam) from the clay. The mould of Nabi Aadam (‘alaihis salaam) was thereafter left until it became dry and would emit a ringing sound like pottery when struck. Thereafter, Allah Ta‘ala blew the rooh (soul) into him. (Majma’uz Zawaa’id #13747)

It is reported in the Hadith of Sunan Tirmizi that due to the composition of Nabi Aadam (‘alaihis salaam) being from different types of sand, the nature, temperament, colour and disposition of his progeny differ from one another. (Sunan Tirmizi #2955)