Guildhall of the Alchemists
From A Wiki of Ice and FireAlchemists' Guild. It is located at the foot of Visenya's Hill, along the Street of the Sisters in King's Landing. The Guildhall is made of black marble, a warren of twists and turns. 
Wildfire, the material that makes the Alchemists' Guild infamous, is prepared in stone cells beneath the guildhall. Above each cell is a room filled with sand. The floor below has protective enchantments placed upon it. Any fire within the cell will cause both floors to fall and the sand to drop, smothering the fire instantly. 
Gallery of the Iron Torches
The Gallery of the Iron Torches is the receiving area for guests. It is a long chamber, empty save for the the columns of wildfire surround black metal columns. The iron torches are rarely lit, usually save for important guests.