+86 731 8800 3666
All Categories


You are here : Home > BLOG

How Does Diamond Have A Hardness Of 10

August 05,2023

Hardness refers to the ability of a material to resist scratches or pressure from other substances on its surface. In practical applications, due to different measurement methods, the material properties represented by the measured hardness are also different. For example, crystal materials use scratch hardness to reflect their ability to resist fracture failure, while metal materials use static indentation hardness to characterize their ability to resist plastic deformation. Static indentation hardness is the process of pressing a hard object into the surface of the tested material under static pressure, and the hardness of the tested object is represented by the load per unit area of the surface pressed into the concave surface. Therefore, there is no unified definition of hardness, and various hardness units are also different, with no fixed conversion relationship between them. According to different test methods, the commonly used ones are Shore hardness, Brinell hardness hardness, Babbitt hardness, Rockwell hardness (the appearance of the hardness tester is shown in the figure), Vickers hardness, microhardness, Mohs hardness, etc.

Diamond is the hardest material in the world. Scientists classify the Mohs hardness of materials into 10 levels, with level 1 being called 1 degree. Diamond has a hardness of 10 degrees and is known as the king of hardness!

The hardness of the material depends on its chemical composition and material structure. The smaller the ionic radius, the higher the ion electricity price, and the smaller the coordination number, the greater the binding energy, the stronger the resistance to external force scratching and indentation, and therefore the greater the hardness.

There are two types of hardness scales, one is absolute hardness, and the other is relative hardness. For example, Mohs hardness is a type of relative hardness that does not indicate the degree of softness or hardness, but only the order of hardness from small to large. Materials in the later order can scratch the surface of the previous material.

The hardness commonly referred to in mineralogy mostly refers to Mohs hardness, which is a standard for representing mineral hardness. This method was founded by German mineralogy professor Mohs’ Friedrich in 1824. The method to determine this standard is to use a pyramid shaped diamond drill needle to scratch the surface of minerals, resulting in scratches. The measured depth of the scratches is used to represent the hardness. Generally, ten common minerals are used as the standard to scrape each other to distinguish between hard and soft, and Mohs hardness is traditionally used in mineralogy or gemmology.

Diamond has a stable tetrahedron structure. Each carbon atom forms a covalent bond with the atoms arranged on the corners of its adjacent tetrahedron. The bond length between carbon atoms is short. This short covalent bond has a strong deformation resistance, so diamond has a great hardness. Since its first discovery by humans over 2700 years ago, diamond has been considered the hardest material in nature.

When using, use standard minerals to delineate each other with the measured minerals of unknown hardness. If the mineral can be scratched by apatite but not fluorite, the hardness of the mineral is 4-5. When there is no standard hardness mineral, it can also be measured with daily necessities. For example, nail hardness is 2.5, coin hardness is 3.5, blade hardness is 5.5, and glass hardness is 6. Almost all minerals greater than 6 should belong to gemstones. As gemstones, they usually have high hardness. For example, the hardness of opal is 5.5~6.5, crystal is 6.5~7, and zinc spinel is 7.5~8. The hardness of chrysoberyl is 8.5, and that of sapphire and ruby is 9, which is second only to diamond.

Accurate determination of mineral hardness requires the use of a microhardness tester or hardness tester. For example, a microhardness tester is actually a microscope equipped with a loading device. Diamond is currently the hardest substance on Earth. The following table compares the hardness of diamond with some other hard materials. The Knoop hardness of diamond is approximately 8.5 times that of quartz, 4.4 times that of corundum, 3.7 times that of tungsten carbide, 3.1 times that of boron carbide, and 1.56 times that of cubic boron nitride.

Comparison Table of Hardness between Diamond and Some Hard

The hardness of diamond has directionality, the hardness of octahedron crystal surface is greater than that of rhombic dodecahedron crystal surface, and the hardness of rhombic dodecahedron crystal surface is greater than that of hexahedron crystal surface. The friction coefficient of diamond in air is extremely small, only around 0.1. Therefore, the wear resistance and grinding ability of diamond are the best among all grinding materials.

Our products scope:
(1) Monocrylline
(2) RVD
(3) Micron-powder
(4) CBN
(5) CBN-micron-powder
(6) Coated-diamond

Related product details information:
(1) Mono-crystal Diamond:

(2)RVD Crushed diamond HFD1211:

(3)Crushed resin diamond micron powder HFD-MPBM:

(4)Black Color HFD-C05 diamond CBN powder with Good Friability and Self-Sharpen Ability:

(5) CBN(Cubic Boron Nitride) Micron Powder Abrasive HFD-CM1:

(6) Copper-coated Synthetic Diamond Powder:

Contact Us:
Changsha Hengfeng Superhard Materials Co., Ltd.
Add: No. 485 Tongzipo Road, Changsha, 410013, China.
TEL: +86 731 8800 3666 ;
mail: [email protected]
Web: https://www.hfdiamondpowder.com/index.html

Table of Contents