How to get a truly clear glass effect for a circle

I'm using .glassEffect(.clear) on a transparent circle over a gradient background. While it's closer to clear than the plain glass effect, it't not really clear, like clear glass. Here is the code. Is there a glass effect that really looks like clear glass?

                Circle()
                    .fill(.clear)
                    .frame(width: 180, height: 180)
                    .glassEffect(.clear)

FYI the best example of a standard control clear effect I want to emulate is the clear effect of a slider thumb when active.

How to get a truly clear glass effect for a circle
 
 
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