Black magic very early on referenced Egyptian Magic.
Early references to Black a.k.a. Khem Magic were references to the magic from the egyptian area of the nile river. This region having been known for very fertile black soil.
From this area came the pursuit of Hermetic and Al"chem"ical experiments. Mostly stemming from turning mundane shit into gold.
Khem = chem
Alchemy = Study of black arts
This did not mean the study of Black/Satanic arts.
That shit would come along only in the last few hundred years.
Prior to that, these subjects of alchemy and spiritual/hermetical arts were only privy to monks, mystics, sages, and rabbis.
This is where the original "black magic" comes from.
The work "magic" comes from "magoi" or "magi".
The Magi came to see Jesus in the manger and bring Gold Frankincense and Myrrh