How to identify the age, author and economic value of rubbings with inscriptions?

1, year: If you have "several pairs", it should be a complete pair. China's past inscriptions record the time of writing, lettering and even the time of setting up the monument.

2. Author: Except for ordinary tombstones, other inscriptions in ancient China generally recorded the author, author and engraver.

3. Economic value: mainly consider the following factors: 1, the age of the monument; 2. The scale of the event and the title of the characters recorded in the inscription; 3. From the perspective of calligraphy, what is written is the size of the inscription and its position in the history of calligraphy; 4, the integrity of the inscription, the appearance of the word (such as the clarity of the word) 5, the amount of existence; 6. Who will buy it?