Copy <Rock:GradientLabel Text="Rock Solid Church" FontSize="50" HorizontalTextAlignment="Center" FontAttributes="Bold">
<Rock:GradientLabel.TextBrush>
<LinearGradientBrush StartPoint="0, 0" EndPoint="1, 1">
<GradientStop Color="Yellow" Offset="0.0" />
<GradientStop Color="Red" Offset="0.25" />
<GradientStop Color="Blue" Offset="0.75" />
<GradientStop Color="LimeGreen" Offset="1.0" />
</LinearGradientBrush>
</Rock:GradientLabel.TextBrush>
</Rock:GradientLabel>
Copy <Rock:GradientLabel Text="Radial Solid Church" FontSize="50" HorizontalTextAlignment="Center" FontAttributes="Bold">
<Rock:GradientLabel.TextBrush>
<RadialGradientBrush Center="0.5,0.5">
<GradientStop Color="Red" Offset="0.1" />
<GradientStop Color="DarkBlue" Offset="1" />
</RadialGradientBrush>
</Rock:GradientLabel.TextBrush>
</Rock:GradientLabel>
Alternatively, you can defined a resource in your parent view and reuse the brush.
Copy <StackLayout Spacing="24">
<StackLayout.Resources>
<LinearGradientBrush x:Key="GradientTextBrush" StartPoint="0, 0" EndPoint="1, 1">
<GradientStop Color="Yellow" Offset="0.0" />
<GradientStop Color="Red" Offset="0.25" />
<GradientStop Color="Blue" Offset="0.75" />
<GradientStop Color="LimeGreen" Offset="1.0" />
</LinearGradientBrush>
</StackLayout.Resources>
<Rock:GradientLabel Text="Rock Solid Church"
FontSize="50"
HorizontalTextAlignment="Center"
FontAttributes="Bold"
TextBrush="{StaticResource GradientTextBrush}" />
<Rock:GradientLabel Text="Linear Gradient"
FontSize="50"
HorizontalTextAlignment="Center"
FontAttributes="Bold"
TextBrush="{StaticResource GradientTextBrush}" />
</StackLayout>