This guide is part of an E-Bay guide series on vaseline glass.  Click here to continue on to our guides about Fenton's vaseline glass.   These guides were made possible by the many E-Bayers who contributed photographs to them.  Please leave feedback by clicking the button at the bottom of the page.

Vaseline Glass and Other Glass That Glows

by Curculiosglass

   

1899 Northwood Fluted Scroll & Vine canary glass vase
in daylight (left) and under ultraviolet light (right)

photos by curculiosglass

Introduction:  What is Vaseline Glass?

           Vaseline glass is yellow or greenish-yellow glass that contains uranium dioxide as a colorant.  The uranium content makes the glass fluoresce (glow) bright green under ultraviolet light.  Vaseline glass is a broad category that cuts across other glass categories:  it encompasses both pressed and blown glass manufactured from 1835 onward and includes, for example, carnival, opalescent, stretch, satin, cased and cut glass.  

          Vaseline glass was first produced in 1835 in Bohemia, and first made in America in the 1840's by the Boston & Sandwich Glass Company.  David A. Peterson, author of Vaseline Glass:  Canary to Contemporary, writes that the heyday of American vaseline glass was the late 1880's through 1905.  Most high-quality American vaseline glass predates the late 1930's:  in 1943, with the advent of World War II, the United States government curtailed the liberal use of uranium by glassworks.  In 1959, the government's ban was lifted, and since then several glass companies have produced contemporary vaseline glass.

          There is some disagreement among aficionados about what constitutes true "vaseline glass".  Vaseline Glass Collectors, Inc. (vaselineglass.org), the paramount American vaseline glass organization, endorses the following definition of vaseline glass:   (1) it must be yellow or greenish-yellow by daylight; (2) it must fluoresce bright green under a black light; and (3) the glass must contain uranium dioxide (at least 2%).  (4) In addition, it is generally accepted that vaseline glass is non-opaque glass -- however, opalescent glass (which combines transparent with cloudy glass), satin glass (whose surface is frosted), and transparent glass coated with an iridescent patina such as carnival and stretch glass, are all included under the umbrella of "vaseline glass".  

         Granted, there's a tautological feel to the first part of this definition -- vaseline glass is yellow-green, so if it isn't yellow-green, it's not vaseline glass!  Nevertheless, the requirement that the glass be yellow or greenish yellow is not wholly arbitrary; uranium salts are naturally yellow, and in their purest form tint glass yellow or yellow-green.  In addition, the VGCI's definition accurately reflects what much of the earliest vaseline glass looked like.  In the 1800's and early 1900's', glass-makers referred to vaseline glass as "canary glass" because of its bright yellow coloring.  The 1899 Northwood vase shown above and the 1899 British Davidson tumbler shown below are examples.

A 1899 Davidson "Lemon Pearline" Prince William tumbler
photo by curculiosglass

          "Vaseline glass" is a term imposed retroactively by collectors to describe the yellow and yellow-green uranium-content glass first called canary glass -- as shown in the photo below, the petroleum jelly product known as Vaseline was originally a distinctive yellow-green color, and thus the name seemed to fit the glass.  Vaseline and canary glass have appeared under other names as well.  The British Davidson company, for example, marketed its line of canary glass under the names "Primrose Pearline" and  "Lemon Pearline," and the terms "lemonescent" as well as "citron glass" are sometimes used to describe early English canary glass.  The Massachusetts company Pairpont called its early canary glass "Canaria," while the Fenton Art Glass company of West Virginia, beginning in the 1920's,  marketed its vaseline glass as "Topaz".  (Fenton's vaseline glass is discussed specifically in Part II of this guide.)

         The term "uranium glass" is sometimes used to mean "vaseline glass".  However, employed correctly, the term "uranium glass" is much broader in scope.  According to leading vaseline glass authorities, uranium glass is any form of uranium-content glass, without regard for whether it qualifies as vaseline glass.  Thus, "uranium glass" includes, for example, vaseline glass; uranium-content transparent glass that is not yellow or yellow-green; and even opaque custard glass and Burmese glass, all of which fluoresce bright green under ultraviolet light.

What is Not Vaseline Glass?

An antique jar of yellow-green vaseline
photo by butchiedog_gone_it

          As noted above, vaseline glass must glow green.  Thus, any listing advertising "vaseline glass" that glows purple, orange or any color except green is incorrect.  Not all glass that glows green is vaseline, however.  Vaseline Glass Collectors, Inc., reports that the following forms of glass often marketed as "vaseline glass" are NOT vaseline glass: 

(A) Manganese-content glass.  As discussed below, manganese may cause glass to fluoresce a diluted green or to fluoresce orange.  Such glass is not "vaseline glass," principally because it has no uranium content.

(B) Green uranium glass.  Several varieties of green uranium-content glass fluoresce neon-green under a black light.  These include, for example, Fenton's green opalescent glass made from 1907-1912.  Because by daylight, such glass is not yellow or yellow-green, it is not vaseline glass.

(C) Green Depression glass.  Green Depression glass contains an iron-uranium mixture.  The uranium makes the glass glow green under ultraviolet light, but iron added to the glass mixture may dilute the glass's fluorescence and also makes the glass appear green in daylight.  Because by daylight, such glass is not yellow or yellow-green, it is not vaseline glass.

(D) Fluorescent teal carnival glass.  Some examples of early teal-colored carnival fluoresce green under a black light.  These include, for example, Westmoreland's 1910 carnival Louisa rose bowls.  Because by daylight, such glass is not yellow or yellow-green, it is not vaseline glass.

(E) Custard and Burmese glass.  Because they are opaque, these forms of glassware are excluded from the definition of "vaseline glass".  In addition, neither could be described as strictly yellow or yellow-green -- custard glass is usually white with a yellowish tint, and Burmese glass is a yellowish white blending into pink.

As this list shows, many forms of glass that frequently appear on E-Bay listed as "vaseline glass" don't really qualify for the category, because they aren't yellow or yellow-green. Color  is a serious disqualifying factor in the vaseline-glass world.  The reigning definition of vaseline glass strives to maintain the category's purity through its strict identification with the sickly yellow-green color of old petroleum jelly.  (Am I the only person who finds this funny?)  We'd argue nonetheless that the fluorescent properties of all of the above forms of glass make them interesting, regardless of whether they are labeled "vaseline glass."  A few examples of these vaseline-glass outcasts are shown below.

Fluorescent Manganese Glass

Above is a specimen of the minerals willemite and calcite.
The mineral manganese is a fluorescence "activator"-- in trace amounts,
as shown above, manganese causes willemite to glow bright green
under UV light, and calcite to glow orange-red.

photo courtesy of curculiosglass

          Uranium causes vaseline glass to fluoresce green -- and in its natural state, as a mineral, uranium also causes a variety of ores and rocks to fluoresce green.  Not every mineral that fluoresces green contains uranium, however. The mineral willemite shown above glows bright green under ultraviolet radiation, and yet willemite has no uranium content:  willemite is a zinc silicate made up of the elements zinc, silicon and oxygen.  Willemite also may contain trace amounts of manganese -- and it is this manganese content that makes willemite fluoresce green.  Accordingly, if you are a glass collector, you should not conclude that the mere fact that a piece of glass glows green under a black light guarantees that the piece contains uranium.  

          In the above mineral sample, trace amounts of manganese also cause the mineral calcite (made up of calcium, carbon and oxygen) to fluoresce orange.  According to Thomas Warren, author of Ultraviolet Light and Fluorescent Minerals (1995), pp. 174-176, manganese acts as a "chemical activator" which, in combination with other elements, produces different colors of fluorescence in rocks.  When manganese is present in glass, it similarly activates fluorescence; the color and degree of fluorescence may depend on such factors as the presence of other minerals in the glass, or the glass' exposure to ultraviolet radiation or intense heat.

          Manganese is an element found fairly frequently in glass. One of the primary uses of manganese is to decolorize glass used to make colorless crystal.  All glass contains silicate, and silicate is often derived from sand, which may contain iron impurities that can tint glass a greenish color.  When added to glass containing iron impurities, manganese acts as an oxidizing agent, rendering the iron compounds colorless; the manganese itself also becomes colorless in the process, leaving the glass clear crystal.  

          Manganese also is used to tint glass specific colors.  When manganese oxidizes, it colors glass amethyst or purple.  Heated to high temperatures, manganese imparts to glass a weak yellowish-brown color sometimes called "amber".  Vaseline Glass Collectors, Inc., reports that such yellowish glass is sometimes mistaken for vaseline glass:  "the end product will glow under a black light, but the color is an orange/peach/color OR a lime green color that is much fainter than the bright neon [green of vaseline glass] under UV light"  (vaselineglass.org).  Below is an example of amber glass that contains manganese:

Amber manganese glass under UV light
photo by kansasviking

Under ultraviolet light, manganese glass may emit fairly bright reddish-orange fluorescence.  Such manganese glass is sometimes referred to as "persimmon glass," and, as shown above, can be quite appealing.  

Green Uranium Glass

   

Fenton's green opalescent Reverse Drapery vase, circa 1907,
under daylight (left) and ultraviolet light (right)

photos by curculiosglass

          The seemingly magical fluorescent quality of vaseline glass is a primary source of its popularity; today, vaseline glass is widely sought by collectors armed with hand-held ultraviolet lights.  What accounts for the manufacture of the glass at an earlier time, when pocket UV flashlights were not available?  Even without the use of modern UV lights, uranium-content glass fluoresces when it catches ultraviolet radiation from sunlight.  Author Oliver Sacks writes in his memoir, Uncle Tungsten (2001), that he was fascinated during his childhood by the canary glass panes in his home's front door:  "Canary glass transmitted yellow light and was usually yellow to look through, but fluoresced a brilliant emerald green under the impact of the shorter wavelengths in daylight, so it would often appear to shimmer, shifting between green and yellow depending on the angle of illumination" (p. 229).           

           This effect is most noticeable at dusk.  Glass authority Barrie Skelcher has written in the British Journal of the Glass Association that before the days of cheap available electricity, people would sit around in their living rooms at twilight, hoping to extract the last of the daylight.  At twilight, the ultraviolet part of the light spectrum increases.  The result, Skelcher writes, is that uranium "takes on a ghostly glow" at dusk, which makes uranium-content glass stand out among other glass, an effect also observable at antique fairs as they close for the evening (glassassociation.org.uk/Journal/uranium-2.htm).  This effect occurs whether the uranium glass is yellow or green. 

            The presence of acids and phosphates in glass affects which color uranium will produce; depending on glass composition, uranium may be used to tint glass green, yellow-green or yellow, without the addition of other colorants. (See Samuel Scholes, Modern Glass Practice [1975], p.  315.)   Josef Reidel, the Bohemian glassmaker credited with inventing uranium glass in 1835, christened the glass with two different names:  Annagelb -- for yellow uranium glass; and Annagrun -- for yellow-green uranium glass.  Reidel manufactured both Annagelb and Annagrun from 1835 to 1840.  

            In the last half of the 19th Century, the use of uranium to tint glass a pure green hue as well as yellow-green and yellow became popular.  Definitively green uranium glass was produced in Germany, Sweden and Great Britain as well as Bohemia.  Like vaseline glass, green uranium glass fluoresces green and registers positive on a geiger counter. The green of green uranium glass is quite intense by daylight.  According to  Barrie Skelcher in the Journal of the Glass Association, "the greens of uranium often had that extra bit of life and sparkle, more so than the green produced by iron."  

          Uranium also was used in the United States in the early 1900's to tint glass green.  The Fenton Art Glass Company of Williamstown, West Virginia, for example, used uranium to produce green in at least two kinds of glass.  The first was opalescent glass Fenton issued between 1907 and 1912:  an example is the Fenton green opalescent Reverse Drapery vase shown above.  Several Fenton green opalescent glass patterns made between 1907 and 1912 fluoresce bright green, betraying their uranium content -- others include Boggy Bayou and Water Lily & Cattails.  Fenton also used uranium to tint its later carnival glass green.  Most carnival collectors are familiar with Fenton's yellow-green vaseline carnival -- not all are aware, however, that some of Fenton's lime green carnival pieces are a variety of green uranium glass.  For example, lime carnival Fine Rib and Boggy Bayou vases that glow bright green under a black light are shown in our guide on Fenton's vaseline carnival glass.

          Opalescent glass collectors also may note that green opalescent vases made during the same general period (1907-1912) by the Dugan Glass Company occasionally glow under ultraviolet light.  To our knowledge, at least three Dugan opalescent patterns sometimes fluoresce brightly -- Plain Panels, Ten-Thirteen and Palisades.  E-Bay sellers additionally have reported that opalescent Feathers vases made by the Northwood Glass Co. during the early 1900's occasionally fluoresce neon green as well.  

          Several other varieties of green glass glow.  Sue C. Davis, author of Pictorial Guide to Vaseline Glass (2002) (pp. 148-156) includes in her guide a photographic section on "uranium glass," which shows examples of green transparent, opalescent and stretch glass that were colored with uranium dioxide and that fluoresce green under ultraviolet light.  In addition, the opaque jade-green Depression Era glass known as Jadite also occasionally glows because it contains uranium dioxide:  measuring cups made in the 1930's by the Jeanette Glass Co. of Jeannette, Pennsylvania are an example.  An array of green uranium glass pieces can be viewed at the website of the New Zealand Glass Museum (glass.co.nz/uranium.htm).        

Green Depression Glass

Transparent green Depression glass Fenton Stag & Holly bowl
in daylight, and glowing under ultraviolet light

photos courtesy of tdn0108

            There is a fairly-well established tradition among vaseline-glass lovers of frowning on fluorescent green Depression glass.  Skelcher has written in the Journal of the Glass Association that the green of uranium-content Depression glass pieces is "lifeless" and renders them "difficult to tell apart from their non-radioactive alternatives".  Vaseline Glass Collectors, Inc., as noted, excludes Depression glass from the vaseline glass category because Depression glass is distinctly green, rather than yellow or yellow-green.  The most frequently used colorant in producing green glass is iron oxide.

            Authors Glickman and Fedosky explain in their book, Yellow-Green Vaseline (1998), that during the Depression-glass era, canary glass fell out of vogue in the United States.  Accordingly, glass makers added iron to uranium-content glass to make it less bright and  less yellow.  From 1921 to the early 1930's, for example, Fenton issued  "green transparent glass" in patterns such as Fine and Rib Stag & Holly (shown above).  Such glassware fluoresces green under ultraviolet light.  Fenton's transparent green glass, however, is a much less intense green by daylight than Fenton's earlier green opalescent glassware.    

         Many vaseline-glass collectors maintain that the iron content of transparent Depression glass causes its fluorescence to be diluted.  This claim, however, is not always borne out:  many Depression-glass pieces glow pretty dramatically, and their fluorescence certainly adds to their interest.  The above bowl, while not vaseline glass, is quite attractive.

Fluorescent Teal-Colored Glass

 

A Westmoreland teal carnival glass Louisa rose bowl, circa 1910:
The bowl's blue-green legs fluoresce bright green under ultraviolet light.

photos courtesy of curculiosglass          

          Collectors are occasionally surprised to learn that unlikely colors of glass prove fluorescent.  Amber, aqua, cobalt-blue and even orange glass have proven, upon testing to contain uranium and to glow green under UV light.  A  photograph of a wonderful display of such uranium-glass oddities can be found at the website of Vaseline Glass Collectors, Inc.  (vaselineglass.org/2007gr9.jpgexamples).

          One notable curiosity of the carnival glass world is fluorescent teal-colored glass.  Such glass remains a mystery to us.  The intense neon-green glow of some teal carnival glass suggests that its fluorescence results from uranium content and not from manganese.  Not all teal carnival glass glows:  the examples that we've found were produced by Westmoreland.  The rose bowl shown above was made in 1910, around the same time that Fenton was issuing its green opalescent uranium glass.  Fenton's teal carnival glass from the same period does not, however, fluoresce; nor does teal Imperial or Northwood carnival glass that we've seen.

          Teal carnival glass is a shade of blue-green that could be described as dark turquoise.  Accordingly, fluorescent teal glass does not fall under the VGCI's definition of vaseline glass as yellow or yellow-green.  In addition, even if the carnival glass shown above contains some uranium, the teal coloring would have been achieved by adding other chemicals.  According to Samuel Scholes, author of Modern Glass Practice, p. 311-313, blue and blue-green coloring in glass may be produced through the use of cobalt oxide and copper compounds.  Both iron and chromium, as well as uranium, are used to tint glass green.  

Recommended Resources on Uranium & Vaseline Glass

Websites:

Vaseline Glass Collectors, Inc.  (vaselineglass.org/)
United Kingdom Glass Association (glassassociation.org.uk/Journal/uranium.htm)
Uranium Glass page of The New Zealand Glass Museum (glass.co.nz/uranium.htm)
The Uranium Glass Gallery (1.parkcity.ne.jp/ken-toma/1.2.html)
The Thomas S. Warren Museum of Fluorescence (sterlinghill.org/warren/foreducators.htm)
     (Thanks to E-Bayer krsilber for telling us about this site.)

Vaseline Glass:  Canary to Contemporary, by David A. Peterson (The Glass Press 2002).
The Big Book of Vaseline and Other Uranium Glass,  by Barrie Skelcher (Schiffer Books 2002).
Pictorial Guide to Vaseline Glass, by Sue C. Davis (Schiffer Books 2002).
Yellow-Green Vaseline:  A Guide to Magic Glass, Rev. Ed.,  by Jay L. Glickman and Terry Fedosky (The Glass Press 1998).
Ultraviolet Light and Fluorescent Minerals, by Thomas S. Warren, Sterling Gleason, Richard C. Rostwick & Earl R. Verbeek
        (Thomas S. Warren, Pub.; Williams Minerals, Distributor, 1995).
Modern Glass Practice, 7th ed., by Samuel R. Scholes (revised and enlarged by Charles H. Greene) (CBLS Publishers 1975).

Click here to continue on to our guides about Fenton's vaseline glass: 

Part I:    Fenton's Canary Opalescent Glass
Part II:    Fenton's Vaseline Carnival Glass
Part III:     Fenton's "Topaz" Stretch Glass

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Photo credits:   Many thanks to E-Bayers  butchie_dog_gone_it,  kansasviking and tdn0108,  for generously contributing photographs to this guide.  Rights to all photos belong to the photographers, and pictures should not be used without their permission.  Text is (c) 2008 curculiosglass, all rights reserved.  To locate any E-Bayer whose name is mentioned here, or to visit his or her store, simply click on "SITE MAP" on the bottom of your screen, and then click on "Feedback Forum" on the right top corner of the screen that next appears.  Type or copy the E-Bayer's name into the search blank.  To see our other guides on glass, click on GUIDE INDEX.   Please leave feedback by clicking the button below.