3 good/fine used singles of the 6d dull slate gray - gray violet from the 1860-1867 Imperf Chalon Heads Issue, 4 clear to just touching & wide margins.
Gibbons values these at £300, so we estimate them at $100. The stamps offered here grade between 45 and 66 as follows:
Centering/Margins: 35/70, 40/70
Paper Freshness: 1/5, 4/5, 0/5
Colour: 5/5
Impression: 5/5
Absence of Visible Paper Flaws: 5/5
Perforations: 6/10, 8/10, 10/10
Adjustment for mentioned faults: -20 points.
