https://www.micralox.com/technology/hard-anodizing/

Hard anodizing, also known as hard coat anodizing or Type III anodizing, utilizes a similar process as standard anodizing, but results in harder and thicker coatings. Whereas standard anodized coatings can reach a Rockwell surface hardness rating of 55, hard anodized coatings can be as high as 70 on the same scale;