Using LinearGradients?

I was wondering if I could have an example of how to use LinearGradient in the UX markup file to create a gradient which goes from a colour of my choosing to transparent. Thanks!

Here is a linear gradient going from red (#f00f) to transparent (#f000)

<Rectangle Height="200" Width="200">
        <GradientStop Offset="0" Color="#f00f"/>
        <GradientStop Offset="1" Color="#f000"/>

Awesome, thank you! My problem was I wasn’t putting it within a shape.