Cause: It was cooked and heated by the high-heat underground water in the volcano. Basalt is formed by the slow pouring of magma.
Structure: Basalt has porphyritic structure, massive structure and almond-shaped structure, andesite has porphyritic structure, interwoven structure and pore structure.
Appearance: the appearance of andesite is often spotted, but it is slightly different with different producing areas. For example, the surface of andesite in the north is covered with small black mineral dots, and the basalt particles are so fine that they are almost invisible to the naked eye, and there is a little graininess when touched by hand.
Color: The andesite is mostly black-gray or black, and the eastern andesite is slightly green, because it is cooked and thawed by the underground hot water of the volcano. Basalt is usually dark green or black, with no mineral spots and dense texture.
Characteristics of basalt:
Basalt gravel is black, with irregular size and various specifications, including 0.5- 1cm basalt gravel, 1-2cm basalt gravel, 2-4cm basalt gravel and 4- 10cm basalt gravel, which are mainly used for paving roads.
Exposed stones in basalt gravel, also known as melon seeds stone and stone washing powder, are mainly used for paving high-standard pavements such as airports. Basalt gravel has the characteristics of high strength and hardness, wear resistance, less water consumption, strong compression resistance and strong corrosion resistance.