Antique Bottle Identification: How to Date Old Bottles

To identify an antique bottle, work out how it was made before you read any embossing: the mould seams, the lip, the base and the glass colour together give a date range, and base marks then name the maker. This is the order used by the Historic Glass Bottle Identification & Information Website, written by Bill Lindsey while at the US Bureau of Land Management and now hosted by the Society for Historical Archaeology (SHA). It covers utilitarian bottles made in the US and Canada from the late 1700s to the 1950s.

• Seams. Follow a side seam up the neck. If it runs to the very top of the lip, the bottle is machine-made, which the SHA key places after about 1900. If it fades out below the lip, the bottle is mouth-blown, typically 1820 to 1915.
• Lip. A horizontal seam just under the lip is a neck-ring seam from a machine. A mouth-blown lip was either applied as a separate blob of glass or tooled; tooling often erased the side seam near the top.
• Base. A rough pontil scar means a mouth-blown bottle held on a rod, usual in the first half of the 19th century. A round suction scar points to an Owens Automatic Bottle Machine; a small round valve mark points to a press-and-blow machine.
• Colour. Use it last and only as support (see below).

• Pontil scars. SHA describes glass-tipped, blowpipe, sand and bare iron pontil scars. Pontil rods were gradually replaced from the early to mid 1850s through at least the mid-1860s by the snap case, a tool that leaves little or no mark, so a smooth-based mouth-blown bottle is usually later than a pontiled one.
• Turn-mould bottles. Cylindrical bottles with fine horizontal rings were turned in the mould; SHA dates most between 1880 and 1915, with outliers from the mid-1850s to the early 1920s.
• The seam-height myth. The SHA FAQ calls the idea that the height of the side seam gives an exact date one of the longest-running myths. Use it only to separate mouth-blown from machine-made.

These ranges are from SHA's colour section. Colour narrows a date; it never proves one on its own.

• Pale purple or amethyst glass was decolourised with manganese, which turns purple in sunlight. Most such bottles date from about 1890 to 1920, with outliers from the 1820s to the 1930s.
• Faint straw or yellow tint comes from selenium, used from about World War I and uncommon after the early 1950s.
• Aqua was very common in American bottles from at least 1800 until the 1930s and became uncommon after the 1920s, with exceptions such as some fruit jars.
• Old-style amber is very uncommon after 1890; amber became more uniform after the late 1910s and early 1920s.
• Cobalt blue was used for soda and mineral water bottles from the 1840s into the early 1900s and for inks into at least the 1930s.
• Milk glass was used mainly from the 1870s to about 1920 for cosmetics and toiletries.

Numbers on a bottle base are production codes, not prices or serial numbers. Glass Bottle Marks explains the common kinds:

• Maker's mark. A symbol or letters for the glassworks, for example an I inside a diamond for the Illinois Glass Company of Alton, Illinois; B in a circle for Brockway Glass; M in a circle for Maryland Glass Corporation of Baltimore.
• Mould number. Identifies which of several identical moulds made the bottle, so defects could be traced.
• Plant code. Identifies the factory. On Owens-Illinois bottles it sits to the left of the mark; for example 3 was the Fairmont, West Virginia plant.
• Date code. On Owens-Illinois bottles it sits to the right of the mark. The diamond, oval and I mark was used from 1929; a single digit followed by a period very often means the 1940s, especially 1940 to 1947, and most bottles from the late 1940s to the 1960s have two-digit codes. Any bottle marked DURAGLAS dates from 1940 or later.

Because a single digit can repeat every decade, always read the date code together with the style of the mark and the way the bottle was made.

Usually not much. LoveToKnow's identification guide says only a few old bottles are worth more than about $25. The categories that specialist bottle auctions feature are a good map of where the money is: American Bottle Auctions of Sacramento highlights historical flasks, bitters, western whiskeys and whiskey flasks, medicines, sodas and mineral waters, beers, food jars, inks and poisons.

• Condition comes first. Historic Glasshouse, a bottle dealer and appraiser, calls condition the number one factor, with scratches, bruises, chips and cracks all cutting value.
• Describe it properly. Height, the full embossing, the lip, the base, the colour and honest condition notes are what any buyer or appraiser needs.
• Use sold prices. Historic Glasshouse points to completed auction results, the Polak and Kovels price guides and auction price reports. It notes that bottle auctioneers typically charge sellers 10 to 15 percent.
• The dating site will not value it. The SHA website says value is outside its goals and points readers to price guides and sold listings instead.

• Reading an embossed patent date as the year made. Fruit jars embossed with Mason's 1858 patent were mouth-blown for about fifty years, roughly 1857 to 1908 according to Wikipedia's Mason jar article. A date on the glass is usually a patent or founding date.
• Trusting colour alone. Aqua and amber were made for decades, and a purple tint only shows the glass contained manganese and has been in sunlight.
• Dating by seam height. As SHA notes, it only tells you mouth-blown from machine-made.

Take three photographs: the whole bottle side-on, the lip and neck with a side seam visible, and the base in raking light so the letters and numbers throw shadows. AntiqLens reads the shape, lip and base marks together and suggests a type, maker and date range. Check the result against the seam, pontil and colour clues above.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Prices are copied from the named guide, dealer or auction report with the date we checked it; asking prices are labelled as asking prices, and where a figure could not be confirmed we say so rather than estimate. If you find an error, tell us and we will correct it.