The article says:
Believe it or not.
Yes, there is only one Stone on earth that floats on water. It is the Black Stone that is situated in the south-east corner of the Holy Ka’bah in the Sanctuary of Makkah al-Mukarramah. Jalaal al-Suyooti said: When al-Mutee’ Lillaah bought the black Stone from Abu Taahir al-Qarmati, the hadeeth scholar ‘Abd-Allaah ibn ‘Ukaym came and said: “We have two signs in our stone: it floats on water and it does not get hot in the fire.” So he brought a stone that had been rubbed with perfume and wrapped in brocade to make him think that this was the Black Stone. They placed it in water and it sank; then they put it in the fire and it cracked. Then he brought another stone and did likewise to it, and the same things happened. Then he brought the Black Stone and put it in water, and it floated; then he put it in the fire and it did not get hot. ‘Abd-Allaah said: “This is our Stone.” Abu Taahir al-Qarmati was amazed by this and said: “How did you know that?” ‘Abd-Allaah said: “It was narrated that the Messenger of Allaah SAWS (peace and blessings of Allaah be upon him) said: ‘The Black Stone is Allaah’s right hand on His earth. It will come on the Day of Resurrection with a tongue with which it will testify about those who kissed it in sincerity or otherwise. It does not sink in water and it does not get hot in fire…’”
The Black Stone is the point at which tawaaf begins, at the south-eastern corner of the Holy Ka’bah. It was originally one of the precious stones of Paradise. Its original colour is white like the maqaam (Maqaam Ibraaheem). It is the place where tears should be shed, and where du’aa’s are answered. It is Sunnah to touch it and kiss it. It is the right hand of Allaah on His earth in the sense that it is the place where a man renews his covenant with Allaah and his repentance. On the Day of Resurrection it will testify for all those who touched it. Whoever swears an oath whilst touching it, it is like touching the Hand of the Most Merciful, and touching it erases sins. It is the place touched by the lips of the Prophets, the righteous and pilgrims performing Hajj and ‘Umrah and visiting the holy places. Glory be to Allaah the Almighty.
The Black Stone is the stone which is inset into the south-eastern corner of the Holy Ka’bah on the outside, in a setting of silver. It is the starting-point for tawaaf. Currently it is a meter and a half above the ground.
What is mentioned in the article quoted in the question is true in part, and there is sound (saheeh) evidence for that, but other things mentioned are not true and have no basis.
We have quoted in the answer to question no. 1902 most of the reports narrated in the Saheeh Sunnah concerning the Black Stone. For example, Allaah sent the Black Stone down to earth from Paradise, and it was whiter than milk, but the sins of the sons of Adam turned it black; it will come on the Day of Resurrection with two eyes with which it will see and a tongue with which it will speak and will testify for those who touched it in truth and sincerity. Touching it, kissing it or pointing to it is the first thing that a person does when he wants to circumambulate the Ka’bah (tawaaf), whether he is doing Hajj or ‘Umrah or a voluntary tawaaf. The Prophet SAWS (peace and blessings of Allaah be upon him) kissed it, and his ummah followed him in doing so. If a person is unable to kiss it he should touch it with his hand or with something, and then kiss that thing. If he is unable to do that he should point to it with his hand and say Allaahu akbar. Touching the Stone is one of the things by means of which Allaah erases sins.
With regard to the story of the Qaraamitah stealing the Black Stone and keeping it with them for a long time, this is true. Ibn Katheer said, concerning the events of 278 AH:
In this year the Qaraamitah – who are a heretical sect that follows Persian philosophy and believes that Zaradasht and Mazdak, who used to permit forbidden things, are prophets – started their trouble.
As well as that, they blindly follow everyone who speaks falsehood. The group they managed to corrupt the most were the Raafidis because they are the least wise of people. They are also called Ismaa’eelis (Ismailis) because they are named after Ismaa’eel al-A’raj ibn Ja’far al-Saadiq.
They are also called al-Qaraamitah. It was said that they are named after Qarmat ibn al-Ash’ath al-Baqqaar; and it was said that in the beginning their leader used to tell them to pray fifty times a day, so as to distract them from what he was really up to.
What is meant is that this group became active in this year, then things got worse and reached alarming proportions – as we shall see – when they entered al-Masjid al-Haraam and shed the blood of the pilgrims inside the Mosque around the Ka’bah, and they broke the Black Stone and removed it from its position, and took it with them to their homeland in 317 AH, and it stayed with them until 339 AH, so it was absent from its place in the Ka’bah for 22 years. To Allaah we belong and verily unto Him is our return.
Al-Bidaayah wa’l-Nihaayah, 11/72, 73
With regard to what was mentioned about the Black Stone being the place where tears should be shed, there is a hadeeth to that effect narrated by Ibn Maajah (2945) from Ibn ‘Umar, who said: The Messenger of Allaah SAWS (peace and blessings of Allaah be upon him) turned to face the Stone, then he put his lips on it and wept for a long time. Then he turned and saw ‘Umar ibn al-Khattaab weeping. He said: “O ‘Umar, this is the place where tears should be shed.” But this is a weak (da’eef) hadeeth as stated by al-Albaani in Irwa’ al-Ghaleel, 111. He said: (it is) da’eef jiddan (very weak).
With regard to the hadeeth about the Black Stone being Allaah’s Right Hand on earth, the answer to that is that it is a false (baatil) hadeeth which is not proven from the Prophet SAWS (peace and blessings of Allaah be upon him).
Ibn al-Jawzi said in al-‘Ilal al-Mutanaahiyah: This hadeeth is not saheeh.
Al-‘Ilal by Ibn Al-Jawzi, 2/575. see also Talkhees al-‘Ilal by al-Dhahabi (p. 191).
Ibn al-‘Arabi said: it is a false hadeeth to which no attention should be paid. Shaykh al-Islam Ibn Taymiyah said: It was narrated from the Prophet SAWS (peace and blessings of Allaah be upon him) with an isnaad that cannot be proven; based on that there is no need to discuss its meaning.
Majmoo’ al-Fataawa, 6/397.
With regard to what is mentioned about the Black Stone floating on water, and that it does not become hot in the fire, and that it is the place where du’aa’s are answered – there is no basis for any of this in the Sunnah.
And Allaah knows best.