The correct option is Turquoise.
Explanation
The application of glazed tiles, known as Kashikari or encaustic tiling, was a distinctive decorative feature in medieval Indo-Islamic architecture. This technique was imported from Persia (Iran) and was extensively used to embellish the exteriors of domes and walls, providing color and sheen to the structures.Analysis:
- Turquoise (Correct): Turquoise (a vibrant blue-green) was the most characteristic and predominantly used colour in these glazed tiles. This preference reflects the strong Persian influence, where blue symbolized the sky and water. It served as a striking contrast to the dull grey quartzite or red sandstone masonry used in the Delhi Sultanate and Mughal periods. Notable examples include the tiled domes of tombs in Multan, the walls of Gwalior Fort, and Mughal monuments like Chini-ka-Rauza.
- Red (Incorrect): Red was the natural colour of Red Sandstone, a primary structural material, but not the characteristic colour of the glazed tiles themselves.
- Black (Incorrect): Black was used sparingly, primarily for outlines, calligraphy, or geometric borders within the tile patterns, rather than as the dominant surfacing colour.
- Grey (Incorrect): Grey was the colour of the local Delhi Quartzite stone used in early Sultanate architecture, not the glazed ornamentation.
Key Takeaway:
Turquoise blue was the defining and most frequently used colour in the Persian-style glazed tiles surfacing medieval Indo-Islamic monuments.