ISeries.PointColor
ISeries

property PointColor[Index: Integer]: OLE_COLOR;

Type Library
TeeChartx

Description
The Series PointColor property is an array of TColor values. Each color value corresponds to a different point in the Series.

Example [Visual Basic]:

You can change by coding the point's color. The following code will change the (2+1)rd point color to vbGreen.

TChart1.Series(0).PointColor(2) = vbGreen

It can be done in most Series types.