What is the Difference Between Basalt and Granite?

The main differences between basalt and granite lie in their composition, formation, and properties. Here is a comparison of the two:

• Composition: Basalt is an igneous, volcanic rock with a low silica content of about 53% SiO₂, while granite is an igneous plutonic rock with a high silica content of about 73% SiO₂. Basalt primarily consists of pyroxene, feldspar, and olivine, while granite is made up of quartz, mica, and K-feldspar.
• Formation: Basalt is an extrusive rock, forming at the surface when lava flows extrude onto the Earth's crust and cool. Granite, on the other hand, is an intrusive rock, forming beneath the surface when subterranean magma chambers cool and harden.
• Cooling Rate: Basalt cools quickly from lava on or near the Earth's surface, resulting in fine-grained texture. Granite cools slowly inside the crust, leading to large crystals and a coarse-grained texture.
• Density: Basalt has a density of 2.9, while granite has a density of 2.7-2.8.
• Hardness: Basalt is generally considered to be a harder rock than granite.
• Appearance: Basalt has a dull and soft appearance, while granite has a veined or pebbled appearance. Basalt is available in black, brown, light to dark grey colors, whereas granite comes in black, grey, orange, pink, and white colors.
• Occurrence: Basalt is more common in oceanic crust, while granite is more common in continental crust.

In summary, basalt and granite differ in their composition, formation, cooling rate, properties, and occurrence. Basalt is a volcanic rock with a low silica content, fine-grained texture, and dark color, while granite is a plutonic rock with a high silica content, coarse-grained texture, and lighter color.

Comparative Table: Basalt vs Granite

Here is a table comparing the differences between basalt and granite:

Both basalt and granite are igneous rocks, but they have distinct differences in their origins, appearance, texture, mineral composition, and uses. Basalt is formed from the rapid cooling and solidification of lava, while granite is formed from the slow crystallization of magma beneath the Earth's surface. Basalt has a dark color and fine-grained texture, with a composition rich in iron and magnesium minerals. Granite, on the other hand, has a varied color range and a coarse-grained texture, with a composition rich in quartz, feldspar, and mica.