ActiveCell.DisplayFormat.Interior.Color

ActiveCell.Interior.ColorIndex - one of 56 preset colors

ActiveCell.Interior.Color - RGB color, used like that:

ActiveCell.Interior.Color = RGB(255,255,255)

Range.DisplayFormat.Interior.ColorIndex

Range.Interior.ColorIndex

Public Function iColor(rng As Range, Optional formatType As String) As Variant
'formatType: Hex for #RRGGBB, RGB for (R, G, B) and IDX for VBA Color Index
    Dim colorVal As Variant
    colorVal = rng.DisplayFormat.Interior.Color
    Select Case UCase(formatType)
        Case "HEX"
            iColor = "#" & Hex(colorVal Mod 256) & Hex((colorVal  256) Mod 256) & Hex((colorVal  65536))
        Case "RGB"
            iColor = (colorVal Mod 256) & ", " & ((colorVal  256) Mod 256) & ", " & (colorVal  65536)
        Case "IDX"
            iColor = rng.Interior.ColorIndex
        Case Else
            iColor = colorVal
    End Select
End Function

'Example use of the iColor function to get the background color of selected cells
Sub Get_Background_Color_Selection_Cells()
    Dim rng As Range

    For Each rng In Selection.Cells
        myCell.Offset(0, 1).Value = iColor(rng, "HEX")
        myCell.Offset(0, 2).Value = iColor(rng, "RGB")
    Next
End Sub