Understanding Quartz's Hardness on the Mohs Scale

Quartz is rated at 7 on the Mohs scale of mineral hardness. This scale ranges from 1 (talc), the softest to 10 (diamond), the hardest, with each number representing a mineral that can scratch those below it.

Quartz is a common and durable mineral, often used in various applications such as jewelry and industrial materials. Being rated at 7, it is harder than calcite, which has a rating of 3. To test if something is quartz, you can try scratching it against glass. If the specimen scratches the glass and you think it’s quartz, it probably is, because calcite is only a 3 on the hardness scale.

The Mohs Hardness Scale: An Overview

For a comprehensive understanding, here’s the Mohs hardness scale with some examples of different materials needed to affect each other:

Hardness Mineral Example of Material Needed to Scratch 10 Diamond None 9 Corundum Hard steel 8 Topaz Hard steel 7 Quartz Hard steel 6 Orthoclase Steel knife blade (6.5) 5 Apatite Most glassware (5.5) 4 Fluorite Steel file 3 Calcite Copper penny 2 Gypsum Fingernail 1 Talc Fingernail

The Mohs scale is widely used for identifying minerals and testing their hardness. While it is a useful tool, it’s important to note that the scale is based on the ability of one mineral to scratch another, and not on absolute hardness measures.

Applications of Quartz on the Mohs Scale

Quartz’s high hardness makes it an ideal material for various applications. Its durability and scratch resistance are highly valued in the manufacturing of:

Jewelry Clocks Industrial materials Agricultural tools Optical lenses

Due to its hardness, quartz is also used in construction materials, cutting tools, and abrasives. The high hardness of quartz can be attributed to the strong covalent bonds between the silicon and oxygen atoms in its crystal structure.

FAQs about Quartz Hardness

Question 1: How do you test if something is quartz?

To test if an object is quartz, you can try scratching it against glass. If the specimen can scratch the glass, it is likely quartz, as calcite, which is often confused with quartz, has a hardness of 3, which is much softer.

Question 2: Is it safe to test quartz on glass?

Yes, it is safe to test quartz on glass that you don’t mind getting scratched. However, avoid testing it on important or valued items such as windows or mirrors.

Question 3: What other minerals have a hardness of 7 on the Mohs scale?

Aside from quartz, other minerals with a hardness of 7 on the Mohs scale include:

Topaz Corundum

Both of these minerals are also highly valued for their hardness and are used in various applications, including jewelry and abrasive materials.

Conclusion

Quartz’s hardness on the Mohs scale of 7 makes it an incredibly durable and versatile mineral. Its use in various applications benefits greatly from its high hardness, making it an indispensable material in many industries. Understanding the Mohs scale can help in identifying and working with different minerals, especially when durability and hardness are critical factors.