An unknown mineral is scratched by a penny. it must

The correct answer is It must be softer than a diamond.

Explanation:

One of the ways to determine what type of mineral is being treated is to test its hardness.

By hardness we mean the resistance with which they can be scratched or cut.

There is a scale called the Mohs Hardness Scale which assigns a number from 1 to 10 to each mineral. Being 1 the softest and 10 the hardest. On this scale,a mineral can only be scratched by harder minerals.

Let's give an example: a diamond could easily cut or scratch a glass. However, this would not be the best way to identify it, since any type of mineral that is harder than 5.5 could cut the glass.

So, what corresponds would be to perform this test on another object, such as a penny. A penny has a hardness of 3, while the diamond is ranked 10 hardness. Therefore, it can be scratched by it.

The correct answer is It must be softer than a diamond.

Explanation:

One of the ways to determine what type of mineral is being treated is to test its hardness.

By hardness we mean the resistance with which they can be scratched or cut.

There is a scale called the Mohs Hardness Scale which assigns a number from 1 to 10 to each mineral. Being 1 the softest and 10 the hardest. On this scale,a mineral can only be scratched by harder minerals.

Let's give an example: a diamond could easily cut or scratch a glass. However, this would not be the best way to identify it, since any type of mineral that is harder than 5.5 could cut the glass.

So, what corresponds would be to perform this test on another object, such as a penny. A penny has a hardness of 3, while the diamond is ranked 10 hardness. Therefore, it can be scratched by it.

If we guide ourselves with the Moh´s scale:

Material scratches apatite → material is harder than 5.

Material is scratched by corundum → material is softer than 9.

Conclusion:

The hardness of the unknown material stands between 5 and 9.

Note:  

Both apatite and corundum are defining materials (reference materials in the Moh´s scale). So, you can also give an answer using defining materials:

"It can either be an orthoclase feldspar, a quartz or a topaz".

Hope it helped,

BiologiaMagister

This answer is dedicated to JaySL

Quartz

Explanation:

Quartz is a resistant mineral whose hardness is 7, according to the Mohr's hardness scale. It is made up of silicon and oxygen and very abundant on the earth's continental crust, after feldspar. It is a very hard mineral that crystallizes in the hexagonal system.

It cannot be scratched by a copper penny and also cleavage is absent. They are the most stable rocks that resist weathering and erosion.

Thus, it is a very important mineral that forms the majority of sedimentary igneous and metamorphic type of rocks.

Quartz

Explanation:

Quartz is a resistant mineral whose hardness is 7, according to the Mohr's hardness scale. It is made up of silicon and oxygen and very abundant on the earth's continental crust, after feldspar. It is a very hard mineral that crystallizes in the hexagonal system.

It cannot be scratched by a copper penny and also cleavage is absent. They are the most stable rocks that resist weathering and erosion.

Thus, it is a very important mineral that forms the majority of sedimentary igneous and metamorphic type of rocks.