Vaseline glass vs uranium glass: what's the difference?

The short answer

Uranium glass is the umbrella: any glass colored with uranium, which glows green under UV light. Vaseline glass is one color family under that umbrella: transparent yellow to yellow-green uranium glass. So all Vaseline glass is uranium glass, but not all uranium glass is Vaseline.

Vaseline Glass Collectors, Inc. (VGCI), the US collectors' club, puts it neatly: Vaseline glass is yellow or yellow-green first, and glows green under a blacklight second. If it doesn't glow, it isn't Vaseline, no matter how yellow it looks.

What is Vaseline glass?

Vaseline glass gets its nickname from its resemblance to old-fashioned petroleum jelly, which had a similar greasy yellow-green look. Older catalogs and English collectors also call it canary glass. VGCI notes it can take as little as 0.1 to 0.2 percent uranium dioxide in the batch to get the color.

Its color shifts with the light. A piece that looks yellow under warm indoor bulbs can look much greener in daylight, and phone flash tends to push it greener still. That's one reason we always show pieces under normal light and UV on camera.

Fair warning if you buy from overseas sellers: the name doesn't travel well. In the UK, "Vaseline glass" often refers to glass with an opalescent treatment, and in Australia it can mean glass with an opalescent rim. In Germany, all of it is just Uranglas.

Other kinds of uranium glass

Once you start carrying a UV flashlight you'll find the glow in places you didn't expect. These are the families collectors talk about most:

• Custard glass: opaque, pale cream to yellow glass that glows green. Think of it as uranium glass you can't see through.
• Burmese: opaque glass that shades from yellow to pink, originally made with uranium in the late 1800s. Fenton made its own Burmese starting around 1970, and those pieces glow too.
• Vaseline opalescent: Vaseline glass with milky opalescent edges or hobnails. The opalescent parts and the body can glow differently under UV.
• Green Depression glass: some of the green glassware from the Depression era contains uranium and glows. Not all of it does, so test each piece.
• Jadeite: some vintage opaque green jadeite glows and plenty doesn't. Don't assume either way.
• Bluranium: a collector nickname for blue glass that glows green under UV. Blue in daylight, green in the dark.
• Other glowing colors: collectors also chase pieces that glow orange or red from cadmium or selenium. Those are fun, but that glow isn't uranium.

Is Vaseline glass worth more than other uranium glass?

There's no blanket rule. Value comes from maker, pattern, form, rarity and condition, same as any glass. A clean, early pressed Vaseline piece in a sought-after pattern can bring real money. So can an HTF custard or Burmese form. A common modern Vaseline toothpick holder won't.

What does matter across the board: condition (check rims, feet and handles for flea bites), a strong glow, and knowing whether you're looking at an original or a later reissue. For current prices, look at recently sold listings rather than asking prices.

Old vs new: reproductions and reissues

Uranium glass was made from the 1800s through about World War II, paused, then resumed after uranium restrictions eased in late 1958. Makers like Fenton and Mosser made uranium glass in the decades after, and some decorative pieces are still made today. New Vaseline glass glows just as bright as old Vaseline glass.

So when a listing says "antique Vaseline" because it glows, that's not evidence of age. Look for maker marks (a Fenton oval logo, for example, points to 1970 or later), crisp versus worn mold detail, base wear, and whether that shape is known to have been reproduced.

How to tell them apart in your hand

Step one is always the same: get a 365nm UV flashlight and a dark room. If it glows green, it's uranium glass. Then sort it by what it looks like in normal light.

• Transparent yellow to yellow-green: Vaseline glass
• Opaque cream to yellow: custard glass
• Opaque yellow shading to pink: Burmese
• Transparent green: often green Depression or other green uranium glass, not Vaseline by the collectors' definition
• Blue in daylight, green under UV: what collectors call bluranium
• Doesn't glow green: not uranium glass, whatever the color

Seeing the difference live

This is honestly easier to show than to describe. On our shows we put Vaseline, custard and the odd bluranium piece under the light side by side, so you can see how differently they look before the lights go out and how alike they look after. Come hang out on Whatnot and we'll put whatever you're curious about under the UV.

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