Khilwat Mubarak: This was the seat of Asaf Jahi dynasty. The Durbar hall has a marble platform. I found this written in a board over there:
The heart of the palace complex is the awe inspiring Khilwat Mubarak, with it’s resplendent chandeliers and marble throne. It was here that the Nizam held Durbars on the most solemn and important occasions. Nobleman, and officials who were commanded to attend, sometimes slept the night in the palace grounds to be on time for the durbars. The last Asaf Jahi occasion to be solemnized at the Chowmahalla Palace was the coronation of the Nizam VIII on 6th April 1967.
Takht-e-Nishan or The Royal Seat:
Video of Khilwat Mubarak:
Chandeliers from Belgium:
Ceiling of the hall: