It is true that raw vinyl itself is colorless. The black color is due to carbon added in, which serves to make the vinyl much more durable. It hardens the vinyl, and also helps the stylus glide smoothly over it. Some of the other coloring agents used in "colored" vinyl do not confer the same increased durability, so some colored-vinyl records won't last as long, and may experience audible sonic degradation after a limited number of plays. Clear vinyl records (no colorants added) will also suffer from this reduced lifespan, compared with the carbon-infused ones. However, for the initial plays, some of the non-carbon vinyl may actually sound even better. Better sound, but for fewer plays. Most of the time, black vinyl is considered the best overall compromise, which is why it is so commonly used.
With the earlier 78 records, the situation wtih additives was even worse. They actually added abrasive particles to the mixture, to grind down the tip of the needle (stylus) as it worked through the groove. The initially blunt, round tip would be shaped through abrasion to better fit the groove, even before the first side of a record had been played. That's why people would buy those little tin boxes of 100 needles; you had to replace the gfound-down needles regularly. The ideal was after each record was played, although most people played a number of records before deciding the needle was ground down too far/thin.
With modern vinyl formulations and today's light tracking forces, and assuming the TT is properly set up, records can be played hundreds of times without the need to replace the stylus, and without noticeable wear on the record. Nice, huh?!
(Amazing what you learn if you hang around AK long enough, huh?
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