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Brilio.net - Have you ever played with rocks as a child and wondered, "How did these rocks form?" One answer is in igneous rocks! Igneous rocks are formed from magma or lava that cools and hardens, like a cake frozen by nature. The formation process can take a very long time, even millions of years! That's why igneous rocks have different shapes and characteristics.
In school, we usually learn about igneous rocks in science or geography classes. Teachers often explain how these rocks are formed and their types, because igneous rocks play an important role in the formation of our earth.
In addition to being interesting to study, igneous rocks also have many uses, ranging from building materials, jewelry, to scientific research. So, it is very important for us to know the various types of igneous rocks.
Are you curious about the types of igneous rocks? Let's explore them together! Who knows, after this you might become better at geology. Ready to learn more? Let's get started!
1. Intrusive Igneous Rocks (Plutonic).Intrusive igneous rocks form when magma cools and crystallizes beneath the Earth's surface.
Characteristics:
- Rough texture due to slow cooling process
- Mineral crystals are clearly visible to the naked eye.
- Generally harder and denser than other igneous rocks
Example:
1. Granite
- Color: White, gray, or pink
- Composition: Quartz, feldspar, and biotite
- Uses: Building materials, kitchen countertops, tiles
2. Diorite
- Color: Dark gray to black
- Composition: Plagioclase and hornblende
- Uses: Decorative stone, building materials
3. Gabbro
- Color: Black or dark green
- Composition: Plagioclase and pyroxene
- Usage: Monumental stone, wear-resistant building materials
Functions in Daily Life:
Granite: Often used as kitchen countertops because it is heat and scratch resistant. Also popular as flooring and wall tiles in luxury buildings.
Diorite: Used as an ornamental stone in gardens and landscapes because of its attractive appearance. Also used in making sculptures.
Gabbro: Because of its resistance to weathering, it is often used for tombstones and monuments. In industry, it is used as an abrasive material.
2. Extrusive Igneous Rocks (Volcanic).Extrusive igneous rocks form when lava cools and hardens on the Earth's surface.
Characteristics:
- Smooth texture due to fast cooling process
- Mineral crystals are difficult to see with the naked eye.
- Often has small holes due to gas bubbles
Example:
1. Basal
- Color: Black or dark grey
- Composition: Plagioclase and pyroxene
- Uses: Building stone, asphalt mix
2. Obsidian
- Color: Glossy black
- Composition: High silica
- Use: Prehistoric cutting tools, jewelry
3. Pumis
- Color: Light gray to white
- Composition: Lots of air bubbles
- Uses: Pumice stone, mild abrasive
Functions in Daily Life:
Basalt: Used in making paving blocks for roads and sidewalks. Also used as aggregate in making fire-resistant concrete.
Obsidian: In addition to jewelry, it is also used in modern surgical blades because of its incredible sharpness.
Pumis: Often used in foot care products to soften the skin. Also used in industry as an abrasive and polishing agent.
3. Hypabyssal Igneous Rocks.Hypabyssal igneous rocks form between intrusive and extrusive igneous rocks, usually at intermediate depths.
Characteristics:
- Texture between rough and smooth
- Often forms tabular or plate structures
Example:
1. Diabase
- Color: Dark gray to black
- Composition: Plagioclase and pyroxene
- Use: Building stone, railway ballast
2. Porphyry
- Color: Varies, depending on composition
- Composition: Large crystals in a fine matrix
- Uses: Ornamental stone, mineral deposit indicator
Functions in Daily Life:
Diabase: Because of its strength, it is often used as a building foundation stone. It is also used as ballast on railroad tracks to stabilize the tracks.
Porphyry: Apart from being an ornamental stone, it is also used in the mining industry as an indicator of the presence of valuable mineral deposits.
4. Pegmatite Igneous Rocks.Pegmatite is an igneous rock with very large crystals, usually associated with granite intrusions.
Characteristics:
- Very large crystals, can reach several meters
- Often contains rare minerals
Example:
1. Granite Pegmatite
- Color: Varies, often with colorful crystals
- Composition: Quartz, feldspar, muscovite, rare minerals
- Uses: Industrial mineral source, gemstone
Functions in Daily Life:
Granite Pegmatite: An important source of industrial minerals such as lithium used in batteries. Its large crystals are often used in jewelry and mineral collecting.
5. Pyroclastic Igneous Rocks.Pyroclastic rocks are formed from material thrown out during a volcanic eruption.
Characteristics:
- Consists of rock fragments, volcanic ash, and other materials
- Texture varies from smooth to rough
Example:
1. Tuff
- Color: Varies, from white to gray or red
- Composition: Compacted volcanic ash
- Use: Lightweight building materials, cement mix
2. Volcanic Breccia
- Color: Varies
- Composition: Large rock fragments in an ash matrix
- Uses: Indicator of past volcanic activity, ornamental stone
Functions in Daily Life:
Tuff: Used as a lightweight building material, especially in earthquake-prone areas. Also used as an admixture in the manufacture of water-resistant pozzolanic cement.
Volcanic Breccia: Apart from being an ornamental stone, it is also used by geologists to study the history of volcanic eruptions.
(brl/tin)
