If magma makes it to the surface it will erupt and later crystallize to form an extrusive or volcanic rock. If it crystallizes before it reaches the surface it will form an igneous rock at depth called a plutonic or intrusive igneous rock.
http://www.tulane.edu/~sanelson/eens1110/igneous.htm
Silica (SiO2) content - 52%-63%. Uses-can be used as aggregate, fill etc. in the construction and roading industries (often not ideal for concrete aggregate because of high silica content); cut and polished for dimension stone for building facings, foyers etc.
http://flexiblelearning.auckland.ac.nz/rocks_minerals/rocks/diorite.html
This is the extrusive or volcanic environment and results in extrusive or volcanic igneous rocks. Extrusive Environments. When magmas reach the surface of the Earth they erupt from a vent called a volcano. They may erupt explosively or non-explosively.
http://www.tulane.edu/~sanelson/eens1110/igneous.htm
GABBRO is a coarse-grained and usually dark-colored igneous rock. Gabbro is an intrusive rock. It means that it formed as magma cooled slowly in the crust. Igneous rocks with similar composition are basalt (extrusive equivalent of gabbro) and diabase (the same rock type could be named dolerite or microgabbro instead).
http://www.sandatlas.org/rock-types/
The intrusive or plutonic environment is below the surface of the earth. This environment is characterized by higher temperatures which result in slow cooling of the magma. Intrusive or plutonic igneous rocks form here.
http://www.tulane.edu/~sanelson/eens1110/igneous.htm
Rock types. Rock type is usually defined as a particular kind of rock having a specific set of characteristics. Rock types are specific assemblages of minerals (most rocks are composed of minerals). Rocks are much more vaguely defined than minerals. Even rocks within one rock type may have a highly variable composition.
http://www.sandatlas.org/rock-types/
Igneous Rocks are formed by crystallization from a liquid, or magma. They include two types. Magma is a mixture of liquid rock, crystals, and gas. Characterized by a wide range of chemical compositions, with high temperature, and properties of a liquid.
http://www.tulane.edu/~sanelson/eens1110/igneous.htm
Igneous rocks are formed from the solidification of molten rock material. There are two basic types. Intrusive igneous rocks crystallize below Earth's surface and the slow cooling that occurs there allows large crystals to form. Examples of intrusive igneous rocks are diorite, gabbro, granite, pegmatite, and peridotite. Extrusive igneous rocks erupt onto the surface where they cool quickly to form small crystals. Some cool so quickly that they form an amorphous glass.
http://geology.com/rocks/igneous-rocks.shtml
Intrusive Environments. Magma that cools at depth form bodies of rocks called intrusive bodies or plutonic bodies called plutons, from Greek god of the underworld-Pluto. When magma intrudes it usually affects the surrounding rock and is also affected by the surrounding rock.
http://www.tulane.edu/~sanelson/eens1110/igneous.htm
It is produced in volcanic arcs, and in mountain building where it can occur in large volumes as batholiths in the roots of mountains (e.g. Scotland, Norway). Because it is commonly speckled black and white, it is often referred to as salt and pepper rock.
http://flexiblelearning.auckland.ac.nz/rocks_minerals/rocks/diorite.html
what type of rock is diorite
Intrusive igneous rock is diorite. Diorite is a type of intrusive igneous rock.