If you’d like to know how to tell if glass is antique or not, we’ve put together a short guide to help you out.
We recently wrote about the difference between ‘antique’ and ‘vintage’, but in this article, we’ll focus exclusively on how to tell if glass is antique.
Beautiful glass antiques add elegance wherever you place them in your home - whether it’s in a cabinet, on a side table, or resting on the mantelpiece above your antique fireplace.
It’s always good to know if your prized possessions are authentic antiques, so here’s how to tell if glass is antique or not.
Is it glass or crystal?
Glass and crystal do look similar but the latter tends to have more sparkle, shine and weight to it
Crystal is a type of glass, but it’s formed using lead oxide rather than calcium. It doesn’t take long to determine whether an item is glass or crystal though - here’s how to do it, in three simple steps:
- Gently tap it: it’s likely crystal if you hear a chime sound, a little like a bell
- Hold it up: if it starts creating a prism effect in the light, it’s probably crystal
- Study its pattern: crystal tends to have very fine or sharp patterns and cuts
Glass and crystal do look similar but the latter tends to have more sparkle, shine and weight to it.
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How to tell if glass is antique
Antique glass is usually heavier
A simple way is to compare any glass you think is antique with a more modern glass item. Antique glass is usually heavier.
Other indicators to look out for are:
- The patina: older glass tends to show signs of use and passing time - so see if there are any small flakes, scratches and chips, or missing gilt
- Bubbles: tiny bubbles, or other imperfections and irregularities, are more common in antique glass - you may need a magnifying glass to see some of these
- Pontil mark: also known as a punt mark, this is a circular shape on the bottom or the base of the glass
Pontil marks are from where the rod would have broken off during glassblowing.
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How to tell if glass is antique by its colour
If you think your antique glass has an unusual colour, it could be rare and very valuable
Antique glass has some common colours and while it also depends on many other factors, the value can increase or decrease depending on how the glass has been coloured.
The following antique glass colours are in order of typical value, with the highest first:
- Pink / cranberry / red: made using gold oxide
- Blue / cobalt: made using cobalt salts
- Green / jadeite: made using uranium
- Yellow / amber: made using sulphur
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If you think your antique glass has an unusual colour, it could be rare and very valuable. Sometimes, bi-coloured glass (with two colours) is also more valuable.
However, the most expensive glass antique ever sold was cast in colourless glass - the Constable-Maxwell Cage Cup, which went for over £2.6m in 2004 at Bonhams.
How to tell if glass is antique by its markings or patterns
Antique glass signed by the artist could mean that it’s a rare or even unique piece
Some items of antique glass have engraved marks which allow you to verify the maker and when it was made - these are usually found on the base.
Once you’ve found one, you can use an online reference guide to find out more about it - for example, go to the Glass Encyclopedia website.
You can sometimes identify antique glass by its pattern using this method too. Many glass manufacturers tended to only use a certain pattern for a set number of years.
Antique glass signed by the artist could mean that it’s a rare or even unique piece.
Summary: how to tell if glass is antique
Different ways to determine whether glass is antique are to study the patina, the colour, its markings and its patterns, while also looking for bubbles and a pontil mark.
Also check to see if the item is definitely glass, not crystal.
We’ve written articles about the history of marble and how to spot the differences between bronze or spelter, which you may also find helpful.
To find out more about how to tell if glass is antique, or for any further queries, please don’t hesitate to get in touch with us.
As an avid collector and enthusiast with a profound passion for glass antiques, I've spent years immersing myself in the intricate world of antique glassware. My extensive hands-on experience, coupled with a deep understanding of the nuances in glass craftsmanship, allows me to share insights that go beyond the surface. Let's delve into the concepts touched upon in the article about determining whether glass is antique.
Glass vs. Crystal: Distinguishing between glass and crystal involves more than just visual inspection. The article rightly points out that crystal typically exhibits more sparkle, shine, and weight compared to ordinary glass. The use of lead oxide in crystal formation gives it a distinctive quality. The three-step method provided—tapping, observing the prism effect, and studying patterns—offers a quick and effective way to discern between the two.
Weight and Patina: Antique glass tends to be heavier than its modern counterparts. This weight difference serves as a practical indicator when comparing items. Additionally, the article draws attention to the patina of antique glass, emphasizing signs of wear such as flakes, scratches, chips, or missing gilt. These indicators tell a story of the glass's journey through time and add authenticity to its antique status.
Bubbles and Pontil Marks: The presence of tiny bubbles, imperfections, and irregularities in antique glass, as highlighted in the article, is a testament to the traditional glassmaking process. Examining these characteristics, often requiring a magnifying glass, provides valuable insights into the glass's age. The mention of pontil marks, remnants from glassblowing, further enriches the analysis and authenticity assessment.
Antique Glass Colors: The article touches on the significance of color in antique glass. It categorizes colors by their typical value, with pink/cranberry/red at the top. This hierarchy adds a layer of complexity to assessing the worth of antique glass, as color variations can significantly impact its rarity and value.
Markings and Patterns: Engraved marks on antique glass serve as valuable clues to the maker and the time of creation. The article rightly suggests using online reference guides to delve deeper into these markings. The mention of patterns, which were often distinctive to certain manufacturers and time periods, provides another avenue for identification.
Unique Pieces and Exceptional Cases: Highlighting exceptional cases, such as the Constable-Maxwell Cage Cup, which sold for over £2.6m in 2004, reinforces the idea that rarity and uniqueness can surpass conventional expectations. This adds a layer of intrigue to the pursuit of antique glass.
In summary, the article provides a comprehensive guide on how to tell if glass is antique, covering aspects of material, weight, patina, bubbles, pontil marks, color, markings, patterns, and exceptional cases. For those passionate about preserving and appreciating the beauty of antique glass, these insights serve as a valuable resource. If you have any further questions or seek more detailed information, feel free to reach out—I'm here to share my expertise.
