This Ascension stamp (Scott #77) is the second most valuable stamp in the set and also has the second highest denomination in the set. This follows a great rule of thumb - stamp collecting values are generally higher for the highest denominated stamps. Especially for older stamps where high-denomination stamps were produced in greatly reduced numbers.
6Red-lady-in-green-dress-245x300 Printed in 1897 and part of a trial printing, there are only 9 examples of what is recognized as the most expensive Chinese stamp. The stamp is valued at nearly 1.3million USD