VERY RARE!! Colorano Silk 1970 10c Apollo 13 Mission Aborted
Scott # C76
The reason this cover has a date that precedes the American Wool issue is that it was made from a blank. It is still a very scarce issue as very few were made.
Notice the caption on the cachet is printed in blue ink on this issue.
You can see from the example below of another issue that these covers with the purple border are, in fact, Colorano.