# Rockwell scale

> Rockwell hardness scale based on indentation hardness of a material with a 120° diamond spheroconical under 150 kgf

**Wikidata**: [Q502723](https://www.wikidata.org/wiki/Q502723)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Rockwell_hardness_test)  
**Source**: https://4ort.xyz/entity/rockwell-scale


## References

1. Freebase Data Dumps. 2013
2. Quora
3. National Library of Israel
4. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)