Question

The famous "Egyptian blue" colour which appears on Egyptian faience is an alkaline glaze coloured by-

• A. Cobalt
• B. Copper
• C. Crome
• D. Barium

Hint:

Logic Tip: Copper + High Alkaline Glaze = Bright Turquoise (Egyptian Blue). Cobalt = Dark Navy Blue.

Answer 1

The Correct Option is B

Concept:
Egyptian faience is a sintered-quartz ceramic material that displays a vibrant, characteristic surface glaze, most notably in shades of blue and green.

Step 1:
Faience relies on an alkaline flux (salts like sodium carbonate or sodium bicarbonate) mixed with crushed quartz. When fired, these materials fuse to form a glassy surface coating.

Step 2:
The signature vibrant turquoise or "Egyptian Blue" color is achieved by introducing a specific metallic oxide into this highly alkaline base.

Step 3:
In alkaline glazes (those high in sodium/potassium and low in alumina/lead), copper carbonate or copper oxide produces a brilliant, bright turquoise blue. (In lead glazes, copper typically produces a grass green).

Step 4:

• Cobalt: Produces a deep, dark navy blue, not the bright turquoise of Egyptian blue.
• Crome (Chrome): Produces green or pink/red (tin-chrome), not blue.
• Barium: Acts as a flux or matte-former, not a primary blue colorant.

Step 5:
Because copper interacts with alkaline fluxes to create the iconic bright turquoise, copper is the correct colorant. \[ \boxed{\text{(2) Copper}} \]