What Makes A Rock A Rock, From Geological Perspective

 Many things make a rock a rock, like being made of solid matter and not being gaseous. But sometimes it’s hard to describe the exact characteristics without using awkward phrases like “has to have x, y, and z, or it’s not really a rock.” So here I’ve described each and every characteristic that makes rocks different from other kinds of matter. 

What is a Rock?

Rocks are simply solids made of crystals or minerals. A mineral is “a naturally occurring, inorganic solid with a specific chemical composition, widespread characteristic mineralogy, and a well-defined and agreed upon chemical formula.” Most common rocks contain multiple minerals, which may have formed before or after the rock was formed. A rock is a mixture of minerals and other materials. The properties of that material will determine whether the rock is hard or soft. Rocks made from the same minerals will have similar characteristics. This makes it easy to identify rocks by their properties.

Why are Rocks Important?

 Rocks are fundamental to our everyday life. Rocks come in an enormous variety, including the ones we mine for materials and resources and the formation on the Moon and Mars. We extract rocks and minerals like gold, silver, diamonds, coal, oil, salt and use them to manufacture products we use daily such as computers, mobile phones, and cars.

Process Responsible for the Formation of Sedimentary Rocks.


A deposition is when layers of sediment build up over time and solidify into rock. This happens in water or on land, for instance, riverbeds can be made of siltstones or sandstones.

Deposition Environment


Compaction is the next step in the process. The sediment gradually becomes more compacted as pressure from overlying layers builds up.

Rock Compaction

Solidification, and lithification

The third step is solidification, which means the sediment becomes a solid mass. The final step is lithification, which occurs as the sediment becomes denser and turns into rock.

Solidified Rocks

Characteristics of a Rock

1.A Rock has to have Minerals

Rock is made up of minerals. Minerals are substances that are found in nature and have a specific chemical composition (or recipe) and a specific crystalline structure that is, a mineral will form into a particular shape if you look at it under a microscope or magnifying glass. Crystals are minerals that form a specific shape when they're heated up and cooled slowly.

2.Must have One or More Minerals.

Rocks are made up of one or more minerals. As rocks undergo changes, they break down into smaller pieces and become sediment. Over time, this sediment becomes compacted and cemented to form a rock.

3.Must-Have has Been formed By Natural Processes.

Most rocks are formed when an existing rock is altered in some way. These changes can be caused by everything from plate tectonics (the movement of Earth's crust) to erosion (the wearing away of rock by wind and water). Rocks can also become chemically altered by their environment. For example, oxygen in the air rusts iron-bearing minerals, changing them from their original composition.

4.Must-Have These sets of physical properties(Texture, Color, Luster, Hardness, and Density)

Rocks come in many different colors and textures, but all rocks share certain characteristics. The properties of rock will determine whether it's hard or soft depending on the minerals that make up the structure. The minerals that make up a rock can make it appear shiny or dull, smooth or rough, clear or opaque. One rock may be heavy, while another may be light. The size of each grain also affects how it looks and feels. Rocks that have large grains can look different than those with smaller grains, even if they are made up of the same minerals. The hardness of any given rock depends on what minerals make up its structure.

5.How to Analyze a Rock-based on its Hardness?

 The properties of rock will determine whether it's hard or soft depending on the minerals that make up the structure. To find out what makes up a particular rock, you need to do a little examination. The first thing you need to do is take a look at the rock in question. Don't be afraid to touch it, but be careful not to scratch it. If there are any visible cracks, gaps, or bursts in the rock, this is also an indication of how hard or soft the material is. If you think your rock is very hard, it may be due to quartz being present. Quartz is a mineral that has been used for centuries for architectural purposes and has since become popular for jewelry and other decorative purposes. If you're unsure about what quartz looks like, try looking at some real quartz jewelry and see if it resembles yours or not. After you have examined your rock, you should then look at its color and texture. These will give you some idea as to its makeup and whether it's hard or soft. It's also important to note if the rock is shiny, dull, or smooth in appearance.

6.Must Belong to the three classes of Rocks

Rocks are made up of multiple mineral deposits that come together to form solid masses. The rocks formed through this process are called igneous rocks and they're the oldest type of rock on Earth because they form first. Sedimentary rocks come next and metamorphic rocks last.

Igneous Rocks

Igneous rocks form when molten material cools and hardens, usually underground where it's protected from wind and rain. Granite is a good example of an igneous rock. It's made up of many different minerals that can be identified based on their color, shape, and hardness (or softness).

Granite Rock

Sedimentary Rocks

Sedimentary rocks are formed when sediment small particles of things like sand, shells, and pebbles settle in layers over time. The weight of the sediment above compresses it into layers of solid rock. Sedimentary rocks often have interesting patterns because they're formed from layers of different-colored sediment.

Gray Shell

Metamorphic Rocks

 Rocks that form under a lot of pressure are called metamorphic rocks. These rocks are usually very hard because of the pressure, high temperatures, and heat from friction caused by tectonic activity. Metamorphic rocks often look like marble or slate and are used for countertops and floor tiles.



You probably know what makes a rock a rock. And hopefully, you’ve had enough sense not to go about petting that loose rock on the playground! But what exactly does make a rock a rock? That’s kind of the question geologists have been asking themselves for years. After all, there are many types of rocks, each with its own unique makeup. The answer to that question reveals something fascinating and complex and it may even help us cope with the inevitable erosion of our planet.

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