This is, without question, a 20th century bottle, and likely a Clevenger bottle.
There is no one attribute that "nails" the attribution, but the amethyst color is commonly used in modern pieces, the weight of the glass is heavier than originals, the incredibly heavy orange peel effect in the glass rings entirely wrong, and the pontil scar on the base will simply not be the same as a 19th century example. In all of the Clevenger examples I have seen, the pontil mark is within a well-defined concavity - unlike the originals in similar molds.