Question

In which one of the following, metamorphism is possible?
1. Coal to Marble
2. Limestone to Graphite
3. Sandstone to Gneiss
4. Graphite to Diamond

Answer 1

Correct Answer - Option 4 : Graphite to Diamond

The correct answer is Graphite to Diamond.

• Metamorphism is the process of modification in the pre-existing rocks under the influence of changes in surrounding conditions such as temperature, pressure,  and surrounding chemical environment.
• Graphite can be converted into a diamond when subjected to high pressure and high temperatures.
• The graphite-diamond transformation can be achieved directly by subjecting graphite to ultra-high pressures (> 100 kbar) and temperatures ( > 2000°C). 
• If we put graphite under a huge amount of pressure, the carbon atoms will be squeezed together and will rearrange themselves into the more compact crystal structure of diamonds.

Rocks	Classification	Rocks after Metamorphism
Granite	Igneous rock	Gneiss
Basalt	Igneous rock	Laterite
Limestone	Sedimentary rock	Marble
Mudstone	Sedimentary rock	Slate
Sandstone	Sedimentary rock	Quartzite