the Fatwa Department Research Committee - chaired by Sheikh `Abd al-Wahhâb al-Turayrî
The hadîth is related by al-Tirmidhî (2955) and Abû Dâwûd (4693). It is declared authentic by al-Albânî and others.
Abû Mûsâ al-Ash`arî relates that the Prophet (peace be upon him) said: “Allah created Adam from a handful taken from all over the Earth. Therefore, the descendants of Adam came forth corresponding to the Earth. Some are red, some are white, and some are black, and some are intermediate between those. Some are easygoing, some are difficult, some are bad, and some are good.”
We cannot begin to speculate on the actual nature of the earth from which Adam was created or the nature of how that took place or the details of the relationship between the various constituents of the earth that was taken and the features and qualities of Adam’s descendants. We must leave knowledge of such matters to Allah.
However, we do know that Adam was one single person and these various colors and qualities only appeared among his descendants. This is clearly stated by the text itself.
Nowhere does the hadîth tell us how or when those different colors appeared in the human population. Therefore, the hadith does not rule out the possibility of a worldly causal relationship between skin color and environmental factors such as sun exposure and diet.
Regardless of how the variations in color among different human populations took place, it occurred according to Allah’s will and as part of His creation.
Allah says: “And among His Signs is the creation of the heavens and the earth, and the variations in your languages and your colors: verily in that are Signs for those who know.” [Sûrah al-Rûm: 22]
And Allah knows best.
Source: Islam Today