Home >> Science & Nature >> Rocks & Minerals

How to Check the Hardness of Carbide

Carbide indicates a substance made of carbon and another element, like calcium. With a large variety of carbides, it can be difficult to tell one carbide from another. One common test used to identify minerals and gems is the hardness test. Each mineral has a specific hardness, which can be determined through a series of tests against objects with known hardnesses. If you have a mineral kit, you can use the labeled stones to determine the hardness of your carbide. However, if you don't have a kit handy, you can use objects around the house to help narrow the options. All the numbers refer to the Mohs scale of hardness.

Things You'll Need

Mineral kit (optional)
Piece of glass
Piece of quartz
Penny

Instructions

- 1
  Take one mineral from your mineral kit and attempt to scratch the surface of your carbide, if you are using a mineral kit. Continue to test each mineral until one scratches. The scratch indicates that your carbide is either as hard or slightly softer than the test mineral. If the test mineral also has a scratch, your carbide has a hardness equal to the test mineral.
- 2
  Scratch your fingernail against the carbide and determine if it leaves a scratch, if you are not using a mineral kit. If there is no scratch, the carbide is harder than 2 1/2. If there is a scratch, the carbide is softer than 2 1/2. Wipe the carbide after scratching to remove any loose mineral.
- 3
  Scratch the penny against the sample of carbide. If the penny leaves a scratch on the carbide, it is softer than three. Wipe the sample after scratching.
- 4
  Scratch the glass against the carbide and see if it leaves a scratch behind. If the carbide scratches the glass, the carbide is harder than 5 1/2. Carefully wipe the carbide, especially if the carbide scratched the glass. There may be small pieces of glass on the carbide.
- 5
  Scratch a piece of quartz on the carbide. If the quartz does not scratch the carbide, it is harder than seven.

Rocks & Minerals