SchemeColor Property

Returns or sets the color of the specified ChartColorFormat object as an index in the current color scheme. Read/write Long.

This example sets the foreground color, background color, and gradient for the chart area fill on the chart.

With myChart.ChartArea.Fill 
 .Visible = True 
 .ForeColor.SchemeColor = 15 
 .BackColor.SchemeColor = 17 
 .TwoColorGradient msoGradientHorizontal, 1 
End With