> For the complete documentation index, see [llms.txt](https://frinn.gitbook.io/custom-machinery-1.21/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://frinn.gitbook.io/custom-machinery-1.21/creating-custom-machines/machine-appearance/hardness.md).

# Hardness

Customize the machine block breaking speed.

Hardness is a float value used to calculate the breaking speed of the machine block.

The higher the hardness the longer the breaking time.

The default hardness is 3.5.

{% hint style="info" %}
A hardness of -1 will make the block unbreakable (like bedrock).
{% endhint %}

Some comparisons with vanilla blocks : 

* Wool : 0.8
* Stone : 1.5
* Dirt : 0.5
* Obsidian : 50
* Netherrack : 0.4
* End stone : 3

#### Example

```json5
"appearance": {
    "hardness": 42
}
```