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