Although most of those meers are usually dated at 1880-1910 , while doing research on mine, I found that the clear amber could potentially mean that the pipe was made a lot earlier than that. Because of the rarity and extreme difference in price, the clear amber was almost never used for pipe making, of course with some exceptions like private commission pipes for high society people or royalty. If this was not the case it could mean that the pipe was made as early as 1820-1860, or even earlier.
NOTE: These are very speculative research results, since documentation, on the subject, from that time period is almost non existent.