# Properties

You can set an element's properties.

```
element Sand {
    colour "yellow"
}
```

These are all the in-built properties that can be set:

* `colour`
* `emissive` (emissive colour of the element)
* `opacity`
* `visible` (if false, the element will not render in the world)
* `hidden` (if true, the element will not appear in the menu)
* `category` (determines which menu category to appear in)
* `pour` (if true, holding down the mouse button will continue to pour more atoms, default is true)
* `default` (if true, this element will be picked by the dropper when you load the page)

## Custom Properties

You can create your own properties with the `prop` keyword:

```
element Water {
    prop state "liquid"
}
```
