TEXTURE OF IGNEOUS ROCKS PDF



Texture Of Igneous Rocks Pdf

Igneous textures and structures SlideShare. View 3. Igneous rocks.pdf from AA 1Igneous Rocks Learning Objectives Igneous textures (Figure 4.7); Igneous rock names (Figure 4.13); Origin of magma; How magmas evolve; Intrusive igneous, IGNEOUS STRUCTURES The structures of igneous rocks are large scale features, which are dependent on several factors like: (a) Composition of magma. (b) Viscosity of magma. (c) Temperature and pressure at which cooling and consolidation takes place. (d) Presence of gases and other volatiles. 56 56..

AN EASY GUIDE TO THE COMMON IGNEOUS ROCKS

The Texture of Igneous Rocks Geology Rock Pinterest. Geology Laboratory: Igneous Rocks and Processes Revised on 10/13/2011 Page 3 of 10 reaction series contains all of the common iron-forming (ferro-magnesian) minerals. Plagioclase makes up the continuous reaction series. The three minerals at the bottom do not form by …, IGNEOUS TEXTURES PDF - PDF Vision. TEXTURES OF IGNEOUS ROCKS. Today, Geologist working with igneous rocks has to apply a wide range of skills, including the analysis of field relationships. The texture of igneous rocks is formed by as they cool down..

ESS Igneous Rocks Lee 1. The flowchart below illustrates the change from melted rock to basalt. (A) slowly, resulting in fine-grained minerals (B) rapidly, resulting in coarse-grained minerals (C) rapidly, resulting in fine-grained minerals (D) slowly, resulting in coarse-grained minerals The solidification of the melted rock occurred 2. Texture of Igneous Rocks • Controlled by cooling rate – Degree of crystallinity – Vesicularity Igneous Textures • Types of igneous textures • Pyroclastic texture – Fragmental appearance produced by violent volcanic eruptions – Often appear more similar to sedimentary rocks • …

Texture of Igneous Rocks • Controlled by cooling rate – Degree of crystallinity – Vesicularity Igneous Textures • Types of igneous textures • Pyroclastic texture – Fragmental appearance produced by violent volcanic eruptions – Often appear more similar to sedimentary rocks • … IGNEOUS TEXTURES PDF - PDF Vision. TEXTURES OF IGNEOUS ROCKS. Today, Geologist working with igneous rocks has to apply a wide range of skills, including the analysis of field relationships. The texture of igneous rocks is formed by as they cool down.

GEOLOGY – Vol. II - Occurrence, Texture, and Classification of Igneous Rocks - Gezahegn Yirgu ©Encyclopedia of Life Support Systems (EOLSS) Summary In this article, the manner in which igneous rocks occur in nature is introduced, followed by a discussion of the general textural features and appearance of these rocks. Page 1 of 2. Igneous Rocks Outline 1. rock groups a. rocks b. rock cycle 2. igneous rocks a. melt i. lava 1. extrusive ii. magma 1. intrusive b. texture

Igneous rocks form from cooled and solidified magma or lava. When magma cools slowly inside Earth, we get intrusive (plutonic) igneous rocks with large crystals. When lava cools quickly at or near Earth’s surface, we get extrusive (volcanic) igneous rocks with small or no crystals. These may be vesicular, meaning there are As has already been described, igneous rocks are classified into four categories, based on either their chemistry or their mineral composition: felsic, intermediate, mafic, and ultramafic. The diagram in Figure 3.4.1 can be used to help classify igneous rocks by their mineral composition.

In geological studies, the texture of a rock helps in determining its type and origin. In this ScienceStruck article, we will have a closer look at the texture of igneous … The initial growth of crystals in magma is driven by kinetic forces, and the resulting textures can be preserved in rapidly cooled igneous rocks. However, crystals in such rocks have a high surface area with respect to their volume, and hence an excess surface energy. …

Identify the information revealed by igneous texture" 4. 3. Identify how igneous rock color relates to chemical "5. composition" 6. 4. Describe the process of igneous evolution and the role of "7. plate tectonics in it" 8. 5. Describe the environments where basalt accumulates "Learning Objectives (LO) 1. Lecture 5: Igneous Rocks" Start studying Chapter 4 - Igneous Rocks. Learn vocabulary, terms, and more with flashcards, games, and other study tools.

CategoryIgneous rocks by texture Wikipedia. 9-9-2019 · 1.3.2 Texture of igneous rocks. What texture might we expect an igneous rock to have? An igneous rock will contain crystals that grew as the magma cooled. Each crystal will have started to grow unhindered by neighbouring crystals, so an igneous rock therefore has a crystalline texture in which the crystals are randomly oriented., TEXTURES OF IGNEOUS ROCKS EPUB DOWNLOAD Go Articles The result of either extrusive or intrusive cooling is evident in the final texture of the igneous rock. The texture of ….

Lecture 10 Igneous Rocks - YouTube

texture of igneous rocks pdf

Igneous Rocks and Intrusive Igneous Activity. As has already been described, igneous rocks are classified into four categories, based on either their chemistry or their mineral composition: felsic, intermediate, mafic, and ultramafic. The diagram in Figure 3.4.1 can be used to help classify igneous rocks by their mineral composition., Igneous rocks form from cooled and solidified magma or lava. When magma cools slowly inside Earth, we get intrusive (plutonic) igneous rocks with large crystals. When lava cools quickly at or near Earth’s surface, we get extrusive (volcanic) igneous rocks with small or no crystals. These may be vesicular, meaning there are.

Chapter 4 Igneous Rocks Flashcards Quizlet. The initial growth of crystals in magma is driven by kinetic forces, and the resulting textures can be preserved in rapidly cooled igneous rocks. However, crystals in such rocks have a high surface area with respect to their volume, and hence an excess surface energy. …, TEXTURES OF THE IGNEOUS ROCKS* Structure - large-scale features recognizable in the field, such as banding, lineation, jointing, and vesicularity. Texture - refers to degree of crystallinity, grain size, and geometrical relationships between the cons tituents of a rock (fabric)..

Lecture 2 Igneous rocks Lakehead University

texture of igneous rocks pdf

Igneous textures Wikipedia. Lecture 2 Igneous rocks Ch.4 text, pg. 142 • Igneous rocks constitute one of the three rock families • Texture refers to the size, shape and arrangement of minerals’ grains and is an important characteristic of igneous rocks. Grain size records cooling history. https://simple.wikipedia.org/wiki/Igneous_rock 9-9-2019 · 1.3.2 Texture of igneous rocks. What texture might we expect an igneous rock to have? An igneous rock will contain crystals that grew as the magma cooled. Each crystal will have started to grow unhindered by neighbouring crystals, so an igneous rock therefore has a crystalline texture in which the crystals are randomly oriented..

texture of igneous rocks pdf


Description of igneous rocks requires information about crystallinity, grain size, shape of grains, and mutual relations of grains, in addition to that dealing with the composition of the constituent materials. Identify the information revealed by igneous texture" 4. 3. Identify how igneous rock color relates to chemical "5. composition" 6. 4. Describe the process of igneous evolution and the role of "7. plate tectonics in it" 8. 5. Describe the environments where basalt accumulates "Learning Objectives (LO) 1. Lecture 5: Igneous Rocks"

Texture of igneous rocks defines the shape, size and mutual relationship of the constituent minerals. The texture in igneous rocks depends on the following four factors: i) Viscosity of magma ii) Rate of cooling iii) The order of crystallization of the constituent minerals. iv) The If classification and identification was all there was to igneous rocks there would not be much use studying them. We classify rocks to learn what they can tell us about the earth. There are two ideas about igneous rocks that are geologically important. The first idea is that igneous rocks evolve - they change from one kind of rock into another.

Types of Igneous RocksTypes of Igneous Rocks 1)1)Extrusive RocksExtrusive Rocks 2)2)Intrusive Rocks :Intrusive Rocks : These are divided in to two typesThese are divided in to two types Plutonic RocksPlutonic Rocks Hypabyssal RocksHypabyssal Rocks 5. Texture of Igneous RocksTexture of Igneous Rocks Texture means Size, Shape and arrangement of 13-11-2019В В· Introduction to Igneous Rocks. An igneous rock is any crystalline or glassy rock that forms from cooling of a magma. A magma consists mostly of liquid rock matter, but may contain crystals of various minerals, and may contain a gas phase that may be dissolved in the liquid or may be present as a separate gas phase.

Download what are igneous rocks ebook free in PDF and EPUB Format. what are igneous rocks also available in docx and mobi. Read what are igneous rocks online, read in mobile or Kindle. Igneous rocks form from cooled and solidified magma or lava. When magma cools slowly inside Earth, we get intrusive (plutonic) igneous rocks with large crystals. When lava cools quickly at or near Earth’s surface, we get extrusive (volcanic) igneous rocks with small or no crystals. These may be vesicular, meaning there are

in the metamorphic rocks did not crystallize from a magma, but they are stable only at high temperatures and pressures found deep in the crust. Light-colored dikes and sills of igneous rock cut the metamorphic rocks. Note the strong vertical fabric of the canyon wall.This pla-nar fabric is characteristic of many metamorphic rocks. Chapter 3: Igneous Textures The texture of a rock is a result of various processes that controlled the rock’s genesis and, along with mineralogy and chemical composition, provides information that we may use to interpret the rock’s Properties of Igneous Rocks. 14.

GEOLOGY – Vol. II - Occurrence, Texture, and Classification of Igneous Rocks - Gezahegn Yirgu ©Encyclopedia of Life Support Systems (EOLSS) Summary In this article, the manner in which igneous rocks occur in nature is introduced, followed by a discussion of the general textural features and appearance of these rocks. ESS Igneous Rocks Lee 1. The flowchart below illustrates the change from melted rock to basalt. (A) slowly, resulting in fine-grained minerals (B) rapidly, resulting in coarse-grained minerals (C) rapidly, resulting in fine-grained minerals (D) slowly, resulting in coarse-grained minerals The solidification of the melted rock occurred 2.

Identify the information revealed by igneous texture" 4. 3. Identify how igneous rock color relates to chemical "5. composition" 6. 4. Describe the process of igneous evolution and the role of "7. plate tectonics in it" 8. 5. Describe the environments where basalt accumulates "Learning Objectives (LO) 1. Lecture 5: Igneous Rocks" 13-11-2019В В· Introduction to Igneous Rocks. An igneous rock is any crystalline or glassy rock that forms from cooling of a magma. A magma consists mostly of liquid rock matter, but may contain crystals of various minerals, and may contain a gas phase that may be dissolved in the liquid or may be present as a separate gas phase.

Igneous Rocks And Processes Download eBook pdf epub

texture of igneous rocks pdf

05- Igneous Rocks.pdf docs.google.com. IUGS CLASSIFICATION OF IGNEOUS ROCKS PDF - 1 Sep In order to create a sustainable classification of igneous rocks which all geologists might use, an international body was set up by the IUGS: the., Igneous Rocks PPT Presentation PDF: There are 3 nice classes of rocks, igneous, sedimentary and metamorphic, and most of the time, they are easy to inform apart. They’re all connected to the endless rock cycle, moving from one type to a different and dynamic ….

The Texture of Igneous Rocks Geology Rock Pinterest

CategoryIgneous rocks by texture Wikipedia. Texture of Igneous Rocks • Controlled by cooling rate – Degree of crystallinity – Vesicularity Igneous Textures • Types of igneous textures • Pyroclastic texture – Fragmental appearance produced by violent volcanic eruptions – Often appear more similar to sedimentary rocks • …, 9-9-2019 · 1.3.2 Texture of igneous rocks. What texture might we expect an igneous rock to have? An igneous rock will contain crystals that grew as the magma cooled. Each crystal will have started to grow unhindered by neighbouring crystals, so an igneous rock therefore has a crystalline texture in which the crystals are randomly oriented..

View 3. Igneous rocks.pdf from AA 1Igneous Rocks Learning Objectives Igneous textures (Figure 4.7); Igneous rock names (Figure 4.13); Origin of magma; How magmas evolve; Intrusive igneous TEXTURES OF THE IGNEOUS ROCKS* Structure - large-scale features recognizable in the field, such as banding, lineation, jointing, and vesicularity. Texture - refers to degree of crystallinity, grain size, and geometrical relationships between the cons tituents of a rock (fabric).

Identify the information revealed by igneous texture" 4. 3. Identify how igneous rock color relates to chemical "5. composition" 6. 4. Describe the process of igneous evolution and the role of "7. plate tectonics in it" 8. 5. Describe the environments where basalt accumulates "Learning Objectives (LO) 1. Lecture 5: Igneous Rocks" Lecture 2 Igneous rocks Ch.4 text, pg. 142 • Igneous rocks constitute one of the three rock families • Texture refers to the size, shape and arrangement of minerals’ grains and is an important characteristic of igneous rocks. Grain size records cooling history.

in the metamorphic rocks did not crystallize from a magma, but they are stable only at high temperatures and pressures found deep in the crust. Light-colored dikes and sills of igneous rock cut the metamorphic rocks. Note the strong vertical fabric of the canyon wall.This pla-nar fabric is characteristic of many metamorphic rocks. 13-11-2019В В· Introduction to Igneous Rocks. An igneous rock is any crystalline or glassy rock that forms from cooling of a magma. A magma consists mostly of liquid rock matter, but may contain crystals of various minerals, and may contain a gas phase that may be dissolved in the liquid or may be present as a separate gas phase.

Volcanic (extrusive) Igneous Rocks Other Notable Pryoclastic Volcanic Eruptions Igneous Rocks Texture A phaneritic texture • Consists of visible grains • Is formed by very slow cooling below Earth’s surface • Characteristic of plutonic igneous rocks i.e. gabbro, diabase, diorite, granite Igneous Rocks Texture Aphanitic texture Types of Igneous RocksTypes of Igneous Rocks 1)1)Extrusive RocksExtrusive Rocks 2)2)Intrusive Rocks :Intrusive Rocks : These are divided in to two typesThese are divided in to two types Plutonic RocksPlutonic Rocks Hypabyssal RocksHypabyssal Rocks 5. Texture of Igneous RocksTexture of Igneous Rocks Texture means Size, Shape and arrangement of

Igneous Rocks PPT Presentation PDF: There are 3 nice classes of rocks, igneous, sedimentary and metamorphic, and most of the time, they are easy to inform apart. They’re all connected to the endless rock cycle, moving from one type to a different and dynamic … In geological studies, the texture of a rock helps in determining its type and origin. In this ScienceStruck article, we will have a closer look at the texture of igneous …

View 3. Igneous rocks.pdf from AA 1Igneous Rocks Learning Objectives Igneous textures (Figure 4.7); Igneous rock names (Figure 4.13); Origin of magma; How magmas evolve; Intrusive igneous in the metamorphic rocks did not crystallize from a magma, but they are stable only at high temperatures and pressures found deep in the crust. Light-colored dikes and sills of igneous rock cut the metamorphic rocks. Note the strong vertical fabric of the canyon wall.This pla-nar fabric is characteristic of many metamorphic rocks.

ESS Igneous Rocks Lee 1. The flowchart below illustrates the change from melted rock to basalt. (A) slowly, resulting in fine-grained minerals (B) rapidly, resulting in coarse-grained minerals (C) rapidly, resulting in fine-grained minerals (D) slowly, resulting in coarse-grained minerals The solidification of the melted rock occurred 2. If classification and identification was all there was to igneous rocks there would not be much use studying them. We classify rocks to learn what they can tell us about the earth. There are two ideas about igneous rocks that are geologically important. The first idea is that igneous rocks evolve - they change from one kind of rock into another.

ESS Igneous Rocks Lee 1. The flowchart below illustrates the change from melted rock to basalt. (A) slowly, resulting in fine-grained minerals (B) rapidly, resulting in coarse-grained minerals (C) rapidly, resulting in fine-grained minerals (D) slowly, resulting in coarse-grained minerals The solidification of the melted rock occurred 2. ESS Igneous Rocks Lee 1. The flowchart below illustrates the change from melted rock to basalt. (A) slowly, resulting in fine-grained minerals (B) rapidly, resulting in coarse-grained minerals (C) rapidly, resulting in fine-grained minerals (D) slowly, resulting in coarse-grained minerals The solidification of the melted rock occurred 2.

In geological studies, the texture of a rock helps in determining its type and origin. In this ScienceStruck article, we will have a closer look at the texture of igneous … Texture of igneous rocks defines the shape, size and mutual relationship of the constituent minerals. The texture in igneous rocks depends on the following four factors: i) Viscosity of magma ii) Rate of cooling iii) The order of crystallization of the constituent minerals. iv) The

Texture of igneous rocks defines the shape, size and mutual relationship of the constituent minerals. The texture in igneous rocks depends on the following four factors: i) Viscosity of magma ii) Rate of cooling iii) The order of crystallization of the constituent minerals. iv) The View 3. Igneous rocks.pdf from AA 1Igneous Rocks Learning Objectives Igneous textures (Figure 4.7); Igneous rock names (Figure 4.13); Origin of magma; How magmas evolve; Intrusive igneous

GEOLOGY – Vol. II - Occurrence, Texture, and Classification of Igneous Rocks - Gezahegn Yirgu ©Encyclopedia of Life Support Systems (EOLSS) Summary In this article, the manner in which igneous rocks occur in nature is introduced, followed by a discussion of the general textural features and appearance of these rocks. Aphanitic ("AY-fa-NIT-ic") rocks have mineral grains that are mostly too small to be seen with the naked eye or a hand lens, like this rhyolite. Basalt is another igneous rock with the aphanitic texture.

IUGS CLASSIFICATION OF IGNEOUS ROCKS PDF - 1 Sep In order to create a sustainable classification of igneous rocks which all geologists might use, an international body was set up by the IUGS: the. 13-2-2018В В· Diorite, granite, pegmatite are examples of intrusive igneous rocks. Extrusive igneous rock: These rocks erupt onto the surface resulting in small crystals as the cooling takes place quickly. The cooling rate is for a few rocks is so quick that they form an amorphous glass. Basalt, tuff, pumice are examples of extrusive igneous rock.

Geology Laboratory Igneous Rocks and Processes

texture of igneous rocks pdf

Lecture 10 Igneous Rocks - YouTube. Start studying Chapter 4 - Igneous Rocks. Learn vocabulary, terms, and more with flashcards, games, and other study tools., Volcanic (extrusive) Igneous Rocks Other Notable Pryoclastic Volcanic Eruptions Igneous Rocks Texture A phaneritic texture • Consists of visible grains • Is formed by very slow cooling below Earth’s surface • Characteristic of plutonic igneous rocks i.e. gabbro, diabase, diorite, granite Igneous Rocks Texture Aphanitic texture.

Igneous rock ppt SlideShare

texture of igneous rocks pdf

AN EASY GUIDE TO THE COMMON IGNEOUS ROCKS. In geological studies, the texture of a rock helps in determining its type and origin. In this ScienceStruck article, we will have a closer look at the texture of igneous … https://simple.wikipedia.org/wiki/Felsic Igneous Rocks PPT Presentation PDF: There are 3 nice classes of rocks, igneous, sedimentary and metamorphic, and most of the time, they are easy to inform apart. They’re all connected to the endless rock cycle, moving from one type to a different and dynamic ….

texture of igneous rocks pdf


Aphanitic ("AY-fa-NIT-ic") rocks have mineral grains that are mostly too small to be seen with the naked eye or a hand lens, like this rhyolite. Basalt is another igneous rock with the aphanitic texture. IUGS CLASSIFICATION OF IGNEOUS ROCKS PDF - 1 Sep In order to create a sustainable classification of igneous rocks which all geologists might use, an international body was set up by the IUGS: the.

Category:Igneous rocks by texture. Jump to navigation Jump to search. Subcategories. This category has the following 4 subcategories, out of 4 total. A Aphanitic rocks‎ (2 C, 12 Textures of plutonic rocks: Refer to the lab handout on volcanic rocks because many of the same terms apply to plutonic rocks, e.g., crystallinity, grain size, crystal form, shapes and habits. The following textural terms are commonly used for plutonic rocks. These terms are used to

Download what are igneous rocks ebook free in PDF and EPUB Format. what are igneous rocks also available in docx and mobi. Read what are igneous rocks online, read in mobile or Kindle. 13-2-2018В В· Diorite, granite, pegmatite are examples of intrusive igneous rocks. Extrusive igneous rock: These rocks erupt onto the surface resulting in small crystals as the cooling takes place quickly. The cooling rate is for a few rocks is so quick that they form an amorphous glass. Basalt, tuff, pumice are examples of extrusive igneous rock.

Bits of preexisting volcanic rocks are reduced to rubble, mixed with newly erupted material, and blown up in the air. As the material settles down we get rocks with an obvious fragmental component (rhyolite breccia), and if it is very fine we may only see those fragments with a microscope (rhyolite tuff). F) VESICULAR TEXTURE (Open spaces, bubbles) Texture of igneous rocks defines the shape, size and mutual relationship of the constituent minerals. The texture in igneous rocks depends on the following four factors: i) Viscosity of magma ii) Rate of cooling iii) The order of crystallization of the constituent minerals. iv) The

Page 1 of 2. Igneous Rocks Outline 1. rock groups a. rocks b. rock cycle 2. igneous rocks a. melt i. lava 1. extrusive ii. magma 1. intrusive b. texture TEXTURES OF THE IGNEOUS ROCKS* Structure - large-scale features recognizable in the field, such as banding, lineation, jointing, and vesicularity. Texture - refers to degree of crystallinity, grain size, and geometrical relationships between the cons tituents of a rock (fabric).

IGNEOUS STRUCTURES The structures of igneous rocks are large scale features, which are dependent on several factors like: (a) Composition of magma. (b) Viscosity of magma. (c) Temperature and pressure at which cooling and consolidation takes place. (d) Presence of gases and other volatiles. 56 56. Intrusive igneous rocks form from the magma that solidifies beneath the Earth’s surface after it has intruded into the pre-existing rocks. Because igneous rocks form under diverse conditions, they differ widely in texture, mineral composition, and appearance.

British petrography with special reference to the igneous rocks The metadata below describe the original scanning. Follow the "All Files: HTTP" link in the "View the book" box to the left to find XML files that contain more metadata about the original images and the derived formats (OCR results, PDF etc.). Igneous Rocks PPT Presentation PDF: There are 3 nice classes of rocks, igneous, sedimentary and metamorphic, and most of the time, they are easy to inform apart. They’re all connected to the endless rock cycle, moving from one type to a different and dynamic …

13-11-2019В В· Introduction to Igneous Rocks. An igneous rock is any crystalline or glassy rock that forms from cooling of a magma. A magma consists mostly of liquid rock matter, but may contain crystals of various minerals, and may contain a gas phase that may be dissolved in the liquid or may be present as a separate gas phase. Textures of plutonic rocks: Refer to the lab handout on volcanic rocks because many of the same terms apply to plutonic rocks, e.g., crystallinity, grain size, crystal form, shapes and habits. The following textural terms are commonly used for plutonic rocks. These terms are used to

TEXTURES OF IGNEOUS ROCKS EPUB DOWNLOAD Go Articles The result of either extrusive or intrusive cooling is evident in the final texture of the igneous rock. The texture of … Pegmatitic texture occurs during magma cooling when some minerals may grow so large that they become massive (the size ranges from a few centimetres to several metres). This is typical of pegmatites. Phaneritic (phaner = visible) textures are typical of intrusive igneous rocks, these rocks crystallized slowly below Earth's surface.

GEOLOGY – Vol. II - Occurrence, Texture, and Classification of Igneous Rocks - Gezahegn Yirgu ©Encyclopedia of Life Support Systems (EOLSS) Summary In this article, the manner in which igneous rocks occur in nature is introduced, followed by a discussion of the general textural features and appearance of these rocks. Textures of plutonic rocks: Refer to the lab handout on volcanic rocks because many of the same terms apply to plutonic rocks, e.g., crystallinity, grain size, crystal form, shapes and habits. The following textural terms are commonly used for plutonic rocks. These terms are used to

It's amazing how much can be seen and read from the rocks if you know what to look for! That's one of the beauties of being a geologist. Three major groups of rocks are: igneous, metamorphic and sedimentary and what differs them from one another is the way they're formed. Start studying Chapter 4 - Igneous Rocks. Learn vocabulary, terms, and more with flashcards, games, and other study tools.

British petrography with special reference to the igneous rocks The metadata below describe the original scanning. Follow the "All Files: HTTP" link in the "View the book" box to the left to find XML files that contain more metadata about the original images and the derived formats (OCR results, PDF etc.). IGNEOUS STRUCTURES The structures of igneous rocks are large scale features, which are dependent on several factors like: (a) Composition of magma. (b) Viscosity of magma. (c) Temperature and pressure at which cooling and consolidation takes place. (d) Presence of gases and other volatiles. 56 56.

Intrusive igneous rocks form from the magma that solidifies beneath the Earth’s surface after it has intruded into the pre-existing rocks. Because igneous rocks form under diverse conditions, they differ widely in texture, mineral composition, and appearance. It's amazing how much can be seen and read from the rocks if you know what to look for! That's one of the beauties of being a geologist. Three major groups of rocks are: igneous, metamorphic and sedimentary and what differs them from one another is the way they're formed.