1870, 10¢ Brown, "I" Grill, showing bold grill impression of late state "I" grill, single perf flaw, tied by strong strike of cross-roads on blue 1874 folded letter to Costa Rica, magenta "San Francisco Cal, Paid, Oct 17" exchange cds, blue Hellmann Bros. merchant handstamp, couple minor cover flaws including light horizontal file fold, a Very Fine and rare use. Scott No. 139A  $6,000 as off-cover. ONE OF ONLY TWO RECORDED 10¢ I. GRILL USAGES. The Scott catalog recently added separate listings for I. grills used on the 1870 issue. The "I" grills are usually well impressed and measure about 10 to 11 by 10 to 13 points. The "I" grills can be separated into early state and late state based on the shape of the tip of the grill. Early state grills show small tip of the pyramid, while late state grills show the pyramid tips truncated and flat. The Scott catalog does not currently assign a value to on cover usages. $0 (Image)