This site instead attempts to help the user determine some key facts - approximate age & function - about any given utilitarian* bottle/jar based on observable physical characteristics.
Hundreds of specific historic bottles are used as examples within the pages of this website to illustrate the concepts discussed; with luck you may find the specific bottle you have an interest in discussed though typically you will not.
Even given these descriptions beginning often mistake a machine made Owen ring on the base of a bottle with a pontil.
Once the likely bottle age or date range is determined, some examples of other places to look for more information is provided.: -It is about 9" (23 cm) in height and 2 3/8th inches (6 cm) in diameter.
-It is made of thick, heavy glass for its size, weighing almost 1 lb.
(Specifics on what a pontil looks like or how to tell the age based on the mold seam can be found in Bottle Basics.) While these two characteristics are often a strong clue to age, readers will be further helped by developing an understanding how the various categories of bottles changed over time.
To aid beginning collectors and those interested in bottles I have developed a number of bottle time lines.