After writing so many articles on bottles, I have found that many of you are very interested in knowing how old the bottles are that you have in your collection. In case you missed the article on how to tell the age of bottles, I will refresh your memory and then give you a little more information.

If you have found a bottle or purchased one from a thrift store or yard sale for your collection and now you are wondering to yourself, “Is this an old bottle?” “Just how old is my bottle?”, here are a few pointers on how to date your bottles.

If you find a bottle with the words “Federal Law Prohibits the Reuse or Resale of this bottle” on it, it is dated about1933.

If you hold a bottle up to the light and see a seam that starts at the bottom and runs to the top, you can tell the age of the bottle by the seam. The diagram shows that seams on bottles continued all the way to the top by the 1900s. You can refer to the diagram as a reference to date the bottles in your collection.

In the 1860s the formula for glass making changed, and lead was removed from the mix. In an attempt to produce a cheap clear glass, magnesium was added in the glass-making process. The magnesium content caused a chemical reaction to take place. Thus, in time it was noticed that when the glass was exposed to the ultraviolet rays of the sun, the glass would turn purple. By placing a bottle in the window seal at your home or in a sunny spot, the glass will turn purple if it was produced between the 1860s and 1914.

If you have any questions about dating your bottles, stop by or call me at the Louisiana Treasures Museum. The museum is located on Highway 22 West of Ponchatoula and has approximately 3,000 pieces of glass in the collection. For more information on hours of operation or to schedule group tours, call 225-294-8352.

Wayne Norwood is a lieutenant with the St. John the Baptist Sheriff’s Department and owner and operator of the Louisiana Treasures Museum.