It is narrated from Hazrat Abu Musa (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: Allah Almighty created Hazrat Adam from a handful of soil which He gathered from the entire earth. That is why the children of Adam are like the earth itself: some are white, some are red, some are black-skinned, and some are in between. Likewise, some are impure and some are good, some are soft and some are sad, etc.
Hadith Referenceمسند احمد / تتمہ مُسْنَدِ الْكُوفِيِّينَ / 19642