The black stone in the side of the Kaaba, apparently a meteorite, must be familiar to everyone who has visited the Kaaba online. An image search will also bring up innumerable pictures of pilgrims to Mecca who are kissing the stone while circumambulating the Kaaba. The tradition of kissing the stone is thought to have begun with Muhammad himself. According to a pious legend that is still believed, the stone was once white but became black over time as it absorbed humanity's sins. It fell from heaven to the site where Muhammad and his son Ismail built the Kaaba. Science cannot validate or contradict the claim that the stone was once white without analyzing a sample of it---something which will never occur as long as it is felt to be sacred. But a scientific analysis of the matter of the meteorite is not necessary. Centuries before the birth of Islam classical writers clearly identified the stone at Mecca as one of a pair. The other member of the pair fell to Mr. Ida in Phrygia (Anatolia or Turkey) where it was worshiped as an embodiment of Kybele or Cybele, the Mother of the Gods. Some ancient writers even claimed that there was only one stone that must have been taken from Phrygia to Arabia---but that idea is surely wrong, for we know as a matter of historical fact that the Idaean stone was taken to Rome during the Punic wars. But the ancient writers all agree that the Idaean stone had always been black.
The real question is not what color the stone in the Kaaba was when it fell to the earth, but if it embodied a goddess in ancient Arabia, and if so what became of that goddess. The answer to the first part of that question is yes, there was a goddess named Al'lat and the Kaaba was fundamentally her shrine, despite the presence of 360 idols who shared the building with her. The second part of the question is answered by a recurring vision that I have, that she is buried beneath the Kaaba. The act of kissing the sacred stone is an unintended acknowledgment of her presence in Islam. The shape of the silver mounting of the stone is suggestive of a certain part of female anatomy. Such things cannot be mentioned in Islam but are openly discussed in Hinduism, where the black stone with its mounting would be called a Yoni. The goddess involved would be Parvati or Kali. Some commentators make a claim that is sure to infuriate many Muslims, that Allah was once Hubal, a moon god to whom the Kaaba belonged. It may be correct to say that Hubal was the chief god of the Kaaba before the Prophet destroyed the idols that the building housed---but it is not necessary to identify him with Allah.
A picture of the polytheism that prevailed at the Kaaba before Muhammad's reforms is becoming apparent. Many of the calendars in use in "pagan" times---including the prechristian calendar of Rome---featured a year of 360 days plus 5. The 360 days were profane, but the 5 intercalated days were sacred. The 360 minor deities at the Kaaba would have been "day gods", somewhat like the patron saints that used to be popular in Roman Catholicism. Hubal and Al'lat would have been the primary gods of the shrine. Hubal was a moon god and Al'lat was an earth goddess to whom the date palm was sacred. Dates were her gift to mankind and a sign of her sweet nature.
Below: Modern art enthusiasts should appreciate this highly stylized image of Al'lat.