Depression, Carnival and Milk Glass: How to Identify Collectible Glass

Three kinds of American glass turn up again and again in family cupboards, thrift shops and estate sales: Depression glass, carnival glass and milk glass. Each was made in large quantities, and each has a dedicated following of collectors. Each has also been widely reproduced. This guide explains how to recognise them, what the common clues mean, and what actually makes a piece worth more.

Depression glass

What it is

Depression glass is the inexpensive, mass-produced glassware made in the United States from around the late 1920s to the 1940s. It was sold cheaply in shops, and often given away as a promotion with food products, at cinemas or at petrol stations. Major makers included Anchor Hocking, Federal Glass, Hazel-Atlas, Indiana Glass, Jeannette Glass and MacBeth-Evans.

How to recognise it

• Colours: pink, green, amber, blue, yellow and clear are the most common, with cobalt blue, red and others less common.
• Pressed or moulded patterns: most pieces were machine-pressed with all-over patterns, many of them floral or geometric.
• Small imperfections: because it was made quickly and cheaply, Depression glass often has tiny bubbles, slight mould marks, uneven thickness and occasional straw marks. These are normal.
• Mould seams: look for faint lines where the parts of the mould met.
• Usually unmarked: most Depression glass carries no maker's mark. It is identified by pattern.

Well-known patterns

Collectors identify Depression glass by pattern name. A few well-known examples include Cherry Blossom and Adam (Jeannette), Mayfair and Miss America (Hocking), American Sweetheart (MacBeth-Evans), Royal Lace (Hazel-Atlas), and Madrid and Sharon (Federal). Pattern guides with photographs are the best way to match a piece, since many patterns look similar at a glance.

Uranium glass and the UV test

Some glass contains a small amount of uranium as a colourant. Under an ultraviolet (UV) light it glows a vivid green. Collectors call yellow-green uranium glass vaseline glass, and some green Depression glass also contains uranium.

• How to test: shine a UV torch on the glass in a dark room. Uranium glass gives off a bright green glow. Longwave UV torches are inexpensive and widely available.
• What it tells you: the glow confirms uranium in the glass. It doesn't, by itself, prove a piece is old, because some uranium glass has been made in recent decades too.
• Is it safe? Uranium glass gives off a very low level of radiation. It is widely considered safe to display and handle, though many collectors choose not to eat or drink from it.

Other materials can fluoresce under UV in different colours, so the bright green glow is the specific sign to look for.

Carnival glass

What it is

Carnival glass is pressed glass with a shimmering, iridescent surface, created by spraying metallic salts on the hot glass. It was made in the United States from the early 20th century, with the main period running from around 1907 into the 1920s. Major makers included Fenton, Northwood, Imperial, Millersburg and Dugan. It later became a popular prize at fairs and carnivals, which is how it got its name.

How to recognise it

• Iridescence: a rainbow-like, oily sheen on the surface, which shifts as you move it in the light.
• Base colour: hold the piece up to a bright light to see the colour of the glass itself. Common base colours include marigold (orange), amethyst or purple, blue and green. Collectors use the base colour, not the surface sheen, to describe a piece.
• Moulded patterns: detailed patterns such as fruit, flowers, peacocks and grapes, often on the outside as well as the inside.
• Marks: some Northwood pieces carry an underlined "N" mark, but much early carnival glass is unmarked.

Watch for later reissues and reproductions

Carnival glass came back into fashion in the 1960s, and several companies, including Imperial and Fenton, produced new iridescent glass, often using old moulds or designs. Many later pieces were marked by their makers, but marks can be ground off, and some copies of old marks exist, including fakes of the Northwood "N". Later iridescence can look brighter and more uniform than the original finish.

Milk glass

What it is

Milk glass is opaque or semi-opaque glass, most often white. It has been made for centuries, but it was especially popular in America from the 19th century onward and again in the mid-20th century. It also comes in blue, pink, black, and the jade green known as jadeite. Makers include Fenton, Westmoreland, Anchor Hocking and many others.

How to recognise it

• Opaque body: hold it to the light. Some milk glass blocks light completely, while some shows a soft glow.
• "Ring of fire": some older milk glass shows a faint rainbow or amber colour around the edges when held to a strong light. Collectors often treat it as a hint of older glass, but it is not proof by itself.
• Common patterns: hobnail (raised bumps), grape and leaf designs, lacy edges, and animal-shaped covered dishes such as hens on nests.
• Marks: many pieces are unmarked. Some later Westmoreland pieces carry a "WG" mark, and Anchor Hocking's Fire-King line is often marked on the base.

Milk glass was produced in huge numbers, and many patterns were made for decades, so the same design may exist in old and later versions.

Spotting reproductions

All three types have been reproduced, sometimes using original moulds. Some general clues:

• Wrong colour. Many reproductions come in colours or shades that weren't used for the original pattern.
• Crisp, heavy or slippery feel. Some reproductions are thicker or heavier, or feel too smooth.
• Weak pattern detail. Copies made from moulds taken from an original piece often show softer, less defined details.
• Unexpected marks or dates. Some reissues are openly marked with a later date or maker. Indiana Glass, for example, reissued the Madrid pattern in the 1970s as "Recollection".
• No wear. Old glass that has been used normally has fine scratches on the base and rim.

Specific reproductions are best identified with a pattern-specific reference book or collectors' club guide, since the details that separate old and new are often small. Our broader guide on antique, vintage or reproduction covers general signs of age.

What drives value

Most pieces of Depression, carnival and milk glass are common and affordable. Higher prices go to pieces with the right combination of a few factors:

• Pattern and form. Some patterns are scarcer than others, and within a pattern some shapes, such as large serving pieces, pitchers or lidded items, are harder to find.
• Colour. In each pattern, certain colours were made in smaller quantities and are more sought after.
• Condition. Chips, cracks, cloudiness ("sick glass"), worn iridescence and scratches reduce value considerably. Run a finger gently around rims and edges to feel for tiny chips.
• Authenticity. Original pieces are valued well above reissues and reproductions.
• Demand. Interest in particular patterns and colours rises and falls over time.

Prices vary widely, so check recent sold results rather than asking prices. Our guide on how much your antique is worth explains how to do this using eBay's sold filter and auction archives.

Tip: Photograph glass against a plain background with light coming through it, then take a second shot of the base. AI Antique can suggest the type, pattern, period and an estimated price range, and its "Find images on Google" button helps you compare your piece with look-alikes.

For a large or unusual collection, a glass specialist dealer or an auction house that regularly sells American glass can help you sort the scarce pieces from the everyday ones.