Basalt Granite And Obsidian Rock

Molten rock material below the surface is called magma.

Basalt granite and obsidian rock.

Dacite is an extrusive igneous rock. Gabbro andesite pegmatite basalt pumice porphyry obsidian granite and tuff. Basalt is an extrusive or intrusive rock that makes up most of the world s oceanic crust. Obsidian is volcanic glass meaning it has no crystals and consists primarily of silica with just enough impurities to color it whereas basalt is a low silica high iron magnesium igneous rock entirely made of small crystals of various minerals including plagioclase feldspar and usually pyroxene and or amphibole.

Properties of rock is another aspect for basalt vs obsidian. Igneous rocks that solidified within the crust are plutonic or intrusive rocks. It most commonly forms as an extrusive rock such as a lava flow but can also form in small intrusive bodies such as an igneous dike or a thin sill it has a composition similar to gabbro the difference between basalt and gabbro is that basalt is a fine grained rock while. Appearance of basalt is dull and soft and that of obsidian is shiny.

When obsidian breaks it fractures with a distinct conchoidal fracture. The canadian shield of north america contains huge outcroppings surface rocks of granite. The principle minerals that make up dacite are plagioclase quartz pyroxene or hornblende. Associate each rock name granite diorite gabbro rhyolite andesite basalt obsidian pumice scoria tuff and volcanic breccia from the classification chart with the geological setting numbers 1 12 shown on the following diagram.

Basalt is available in black brown light to dark grey colors whereas obsidian is available in black blue brown green orange red tan yellow colors. Magma that has reached the surface is lava. Igneous rocks from left to right. Basalt is fine grained so the individual minerals are not visible but they include pyroxene plagioclase feldspar and olivine these minerals are visible in the coarse grained plutonic version of basalt called gabbro.

This specimen erupted from kilauea volcano in 1960.