Igneous Rock Homework Help

Get customized homework help now!

Igneous Rock

Igneous rock is those which have been ejected in a melted state either from volcanoes or through fissures in the earth's crust. As the crystallizing of superficial deposits may produce rocks like those that are of true igneous origin, the same species in a few cases occur in both divisions. Thus, there are metamorphic diorite and porphyry, as well as igneous diorite and porphyry. The igneous rocks differ from most of the metamorphic series in the absence or very sparing occurrence of quartz.

There are two series of igneous rocks,—the feldspathic, having light colors and being of low specific gravity, and the augitic, having dark colors with high specific gravity.

Feldspathic series: Consisting mainly of a feldspathic base, with, often, disseminated crystals of some kind of feldspar, or of horn­blende or pyroxene. Feldspathic series colors are white, gray, bluish gray, grayish brown, occasionally, as in the porphyries, dark red and brown. The light colors and low specific gravity are owing to the absence or sparing dissemination of iron.

Augitic series: Consisting of feldspar and hornblende or augite (greenish-black or black pyroxene). Augitic series Colors are, dark gray, dark gray­ish brown, dark greenish brown, greenish-black to black. The high specific gravity and dark colors are owing to the presence of iron as magnetic or titanic iron, or as a constituent of the augite or hornblende.

Virtually all the igneous rocks are composed largely of silicate minerals, and any rock type consists of a definite assemblage of minerals, mainly determined by temperature, which can be used to classify the rock. Although through, for example, re-melting, magmas of quite different compositions exist, it is possible to obtain virtually a full range of rock types from a single magma derived from the mantle. Although six types of igneous rock (basalt, gabbro, andesite, diorite, rhyolite, and granite) account for about 90% of all igneous rocks, there is a continuous gradation in the chemical composition of igneous rocks.


  • What are igneous rocks?
  • What are the types of igneous rocks?

Classof1.com is a pioneer in online tutoring and homework help. Our tutors are highly qualified in their subject areas and have been helping students since 2003. For immediate Igneous Rock homework help, use the homework-help form present on this page. You can also get help with your Igneous Rock homework by writing to learning@classof1.com.

For instant assistance, click here to start a live-chat with us.

Earth Science Homework Help
Name* :
Email* :
Country* :
Phone* :
Subject* :
Attachment* :
Upload another homework (upto 5 uploads max.)

Type Your Questions OR Instructions Below
Type this code and send us your igneous rock homework questions to get written lessons from expert igneous rock tutors.
(Type Security Code - case sensitive)
By clicking on the "Get Homework Help" button, you agree to the Terms and Conditions of Classof1.
Classof1.com is a safe, secure and trusted website as certified by Norton Secure (powered by VeriSign)
About Us | Terms of Use | Privacy Policy Copyright © 2002-2014 Classof1. All rights reserved.
Live chat assistance with igneous rock homework help
Live chat assistance with igneous rock homework help