The combustible ice, a kind of natural gas hydrate, is formed under conditions of high pressure and low temperature.
The pure hydrate takes on a white color and could be ignited directly, like the solid alcohol. One cubic meter of the hydrate is equivalent to 164 cubic meters of natural gas.
China is the fourth country to successfully excavate such combustible ice from the sea bed, after the United States, Japan and India.
Two pictures here show Chinese samples of combustible ice excavated from the floor of the northern South China Sea in the southern Guangzhou city. Link
