Basalt Granite And Obsidian Rock

The canadian shield of north america contains huge outcroppings surface rocks of granite.

Basalt granite and obsidian rock.

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. Appearance of basalt is dull and soft and that of obsidian is shiny. The hardness of basalt is 6 and that of obsidian is 5 5 5. Igneous rocks that solidified within the crust are plutonic or intrusive rocks.

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. Properties of rock is another aspect for basalt vs obsidian. Basalt is a dark colored fine grained igneous rock composed mainly of plagioclase and pyroxene minerals. Igneous rocks from left to right.

Basalt is an extrusive or intrusive rock that makes up most of the world s oceanic crust. Magma that has reached the surface is lava. 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.

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. Dacite is an extrusive igneous rock. Gabbro andesite pegmatite basalt pumice porphyry obsidian granite and tuff. Molten rock material below the surface is called magma.

The principle minerals that make up dacite are plagioclase quartz pyroxene or hornblende.