Just to clarify, the word Bleikristall is not a manufacturer or importer / exporter, but the German word for lead crystal which can be found on many German glass factory's wares.
The "Byrde's Collection" was a specific line which was produced by Hofbauer, not sure enough of the bell is pictured to make a definitive attribution to that company or specific line (although it looks very similar).
As md1919 noted, the area you pictured is an "inclusion" which occurred during production and significantly reduces the value (if it is a Hofbauer bell, these are currently selling on R Ltd. for $13.99, so with this issue, much less.)
