Glass - Old or New? Here's a Few Clues!

In 1963 while traveling in Jamaica, I found what was believed to be an authentic Greenhow Williamsburg 1770 sealed old glass bottle.  I actually agonized over the purchase for $30.00.  In 1972 while visiting Williamsburg, I discovered that whole antique glass bottles like this had never been found!  My bottle was presented and alas the curator, Noel Hume, stated that it was not old but rather a 1930s Williamsburg reproduction.  The good news was that at that time it was worth $60.  The color of the bottle was good.  The methods used to produce the bottle were right on.  It had an applied seal.  There was a broken pontil (a rough spot on the bottom where the glass blower broke the pipe away from the object) and the mold marks were polished when it was taken out of the mold.  But, the curator stated that the give away was that it just looked too good.  The bottle would most likely have been used and show wear from use or worse mis-treatment.

This is one of the clues for distinguishing old glass, antique glass from new.  Check the bottom of a piece to see if there are scratches.  Expect to see wear where it makes sense.  The bottom of a bottle would show scratches where it was slid over tabletops.  These marks should not be uniform but rather random in depth, direction, width and length.  Parallel lines or concentric circles would be suspect.  Sandpaper can be used to simulate wear marks.

Reproductions are often made from original molds and museums often offer reproductions for sale.  Checking museum catalogs is a good way to see what is currently being offered and thus not old.  Reproductions from such sources may be marked or tagged but the mark may be with an easily removed paper label and the tag may have been discarded.  And, don’t forget to check out places like Cracker Barrel to see what is new.  You will often see colors in new glass offerings that you will never see in older glass.

Logan Adams is a Certified Personal Property Appraiser and the Owner of The Specialists of the South in Panama City Florida. She is an old glass collector and specializes in antique glass bottles.