Explain how you could estimate the hardness of a mineral that does not appear on the mohs scale?

To estimate the hardness of a mineral not included in the Mohs scale, you could use a scratch test with reference minerals of known hardness. By attempting to scratch the unknown mineral with these reference minerals, you can determine its hardness based on whether it scratches or is scratched. Additionally, you could use more precise methods such as a microhardness tester, which measures the hardness under a specific load and provides a quantitative hardness value.