Mohs scale of mineral hardness
Contents |
[edit] Introduction
Archaeometallurgy, Guidelines for Best Practice, published by Historic England in 2015, defines hardness as: ‘…a measurement of the strength of a material (its ability to resist plastic deformation).’
[edit] Mineral hardness
The Mohs hardness scale designates the hardness class of mineral based material. It is used to describe how substances behave when a hard material scratches a soft material. The scale ranges from 1 to 10, where 1 is talc (softest) and 10 is diamond (hardest).
The scale is named for its originator, Friedrich Mohs. The German geologist created the scale in 1822 as a method for classifying minerals by their physical properties (rather than by their chemical composition).
While this approach differed from scientific contemporary thought, it was aligned with discoveries from the ancient world. Mohs based his scale on the ancient discovery that diamond would scratch quartz, which meant the diamond was the harder substance of the two.
[edit] Ratings
Some key mineral ratings on this scale include:
| Mineral | Mohs hardness rating |
| Talc | 1 |
| Gypsum | 2 |
| Gold, silver, aluminium | 2.5 to 3 |
| Ordinary steel | 4 to 4.5 |
| Diamond | 10 |
The Mohs scale is one of several scales used to describe the hardness of different types of materials. It is considered a useful tool for estimation purposes (since results are immediately visible), but it is not considered an accurate indicator of a material’s genuine endurance characteristics.
[edit] Related articles on Designing Buildings
Featured articles and news
Call for greater recognition of professional standards
Chartered bodies representing more than 1.5 million individuals have written to the UK Government.
Cutting carbon, cost and risk in estate management
Lessons from Cardiff Met’s “Halve the Half” initiative.
Inspiring the next generation to fulfil an electrified future
Technical Manager at ECA on the importance of engagement between industry and education.
Repairing historic stone and slate roofs
The need for a code of practice and technical advice note.
Environmental compliance; a checklist for 2026
Legislative changes, policy shifts, phased rollouts, and compliance updates to be aware of.
UKCW London to tackle sector’s most pressing issues
AI and skills development, ecology and the environment, policy and planning and more.
Managing building safety risks
Across an existing residential portfolio; a client's perspective.
ECA support for Gate Safe’s Safe School Gates Campaign.
Core construction skills explained
Preparing for a career in construction.
Retrofitting for resilience with the Leicester Resilience Hub
Community-serving facilities, enhanced as support and essential services for climate-related disruptions.
Some of the articles relating to water, here to browse. Any missing?
Recognisable Gothic characters, designed to dramatically spout water away from buildings.
A case study and a warning to would-be developers
Creating four dwellings... after half a century of doing this job, why, oh why, is it so difficult?
Reform of the fire engineering profession
Fire Engineers Advisory Panel: Authoritative Statement, reactions and next steps.
Restoration and renewal of the Palace of Westminster
A complex project of cultural significance from full decant to EMI, opportunities and a potential a way forward.
Apprenticeships and the responsibility we share
Perspectives from the CIOB President as National Apprentice Week comes to a close.