Why Does Radiant Early 20th Century Plateware Buzz with Geiger Counters, and Depression Glass Glows under Blacklight?

Uranium was used in ceramic glazes until the mid 1940s. The colourful dinnerware emits a bright glow depending on the colour bought or a green hue when used under ultraviolet light or direct sunlight. It’s not safe to eat on due to its radioactive but okay to store in a house for viewing purposes behind (non-radioactive) glass. The uranium plateware and glassware still radiates radio waves to this day.

A lot of manufacturers used uranium oxide in their glazing process at this time to make vivid colours more radiant for centuries. This practice was popular during the 1920s and 1930s during the Great Depression. Uranium ore was abundant material that produced oranges, yellows, reds, greens, blues, blacks and mauves for any ceramic. Tiles for the bathroom and kitchen during the 1920s to 1940s would contain some sort of uranium compound. Since the Depression era plateware was well known for having uranium there was one set of plateware connected to the radioactive element and that was Fiesta ware.

Fiesta ware was introduced in the early 20th century in 1936. Fiesta ware used at least 4 grams of uranium in the glaze. The colours are very vibrant and cheery. The Fiesta dinnerware was appealing to the Depression era shoppers to brighten people’s day at the table. The plates were heavy and sold by the piece so that it was up to the consumer to build their own collection over time. The colours were fun and came in a variety of selections with mango red the most iconic from the line while medium green is considered the rarest. The designs are open to mix and match with whatever suited the consumer. The word Fiesta is Spanish for party.

1930’s Fiesta ware in Green.
Source: Jim Snydergrant on Flickr

Homer-Lauglin was one of the main companies that started manufacturing these plates in West Virginia. The company started by Homer Laughlin a dn Shakespeare Laughlin in 1871. In 1907, it was the largest pottery house in America. For the early editions on the plates, Fiesta ware would be printed as a lowercase “f”. They gather clay from the Earth. The clay they collect is ball clay for plasticity and strength, kaolin clay for the soft white colour, feldspar for translucence and sanitary non-porous qualities and alpha-alumina for extra strength. Giant machines knead the clay, moulded it and dried it in pottery. They stamp the dinnerware with the logo before glazing it. They glazed twice within the same week. The job is slow and very labour intensive. There are still some hand artists who paint fine lines and details on the pottery.

Uranium was discontinued in 1943 to use in dinnerware due to fuel the war effort for bombs with the element. The uranium went to fuel the Manhattan project during World War Two which was the creation of two atomic bombs Little Boy and Fat Man to be dropped over Japan. Uranium was used for the project for Uranium-235. The Advisory Committee told President Franklin Roosevelt that the element “would provide a possible source of bombs with a destructiveness vastly greater than anything now known.” By 1944 to 1945 uranium was discontinued for public use.

Depleted uranium replaced natural uranium after the American government relaxed their stand on the usage of uranium in 1959 but was taken out of the glaze for safer products by the 1970’s.

Many people use a Geiger counter to test for radioactivity. Most of the tests show the counter always detecting radioactivity with the counter dial at a high and a loud static sound starting to buzz. This would be detecting the beta radiation from the uranium’s decay chain in the glaze. The uranium found on the dinnerware is low but detectable. These plates that test with radioactivity are not safe to eat off on. Hot and acidic foods have a chance to leach off radiation onto the food. Furthermore, if the plate is chipped or cracked could also be dangerous because of contamination. And this goes without saying but this dinnerware is not microwave safe.

A Geiger counter is detecting radioactivity on dinnerware.

A version of Fiesta ware still exist but doesn’t contain radioactive materials and any other heavy metal material like lead. The later ones after 1989 would state that it’s lead-free and Fiesta ware with a capital “F” in the description on the back of the china and have more colours available.

People collect these plates as a piece of Americana culture. The reason why is usually the colourful design and nostalgia. It is one of the most collected dinnerware. Many colours get retired after a while either a year out or a few years on the market.

Green Depression glass – buscuit barrel.
Source: Wikipedia

Depression glass has a similar story of it being from the mid-1920s and 1930s with yellow, green, cobalt blue, amber, clear and pink being synonymous with the product. Unpopular colours being sought after are “alexandrite” which was lavender and tangerine orange by collectors because of rarity. The glassware is a clear translucent embossed glassware that was popular during the Great Depression. They were mostly given out as promotional items for customers to return to the business establishments. They were in low quality with air bubbles, sharp edges on plates, mould/straw marks, inconsistencies and other flaws in the glass that were made during production. The glasses were given out at movie theatres, gas stations or in cereal boxes. The glassware was cheap at a cost of nickel or a dime at a local shop. The design, colour and cost were perfect for people on a budget during the 1930s. Anchor Hocking Glass Company, Indiana Glass Company, Jeannette Glass Company and Imperial Glass Company were a few of the leading companies that made this type of glasses. Well known patterns were the American Sweetheart (1930 to 1936), Cameo (1930 to 1934), Mayfair (1931 to 1937), and Royal Lace (1936 to 1941) for collectors.

There were rare options like Vaseline glass which was a marble patterned and Jadite glass which were opaque pale green glasses. The higher quality type of this glassware is called Elegant glass which was made without imperfections, clear and patterns recessed in the glass than raised.

Glowing Depress Glass under ultraviolet light.
Source: Betta Tryptohan

These glasses had uranium compounds. The uranium was mixed in with colour chips during the moulding process. The glasses glow bright fluorescent green under ultraviolet light with the Geiger counter buzzing off detection of radioactive activity.

They are not microwave safe but not dishwasher safe because a permanent cloudy haze will develop on the glassware. These glasses are prone to chipping, cracking and stress marks. There are collectibles in auction houses and online sales that quadrupled in cost. The reproductions now most likely don’t have uranium.


ThoughtCo. – How Radioactive Is Fiesta Ware?

Paul Frame, Oak Ridge Associated Universities – General Information About Uranium in Ceramics

The Spruce Crafts – Collecting Depression Glass

Dusty Old Things – Depression Glass Used to Cost a Nickel And Now It Can Be Quite Valuable

Invauables – A Collector’s Guide to Depression Glass

Video – The Homer Laughlin China Co. – Made In America Featuring Homer Laughlin China

Video – US Foods CES – Homer Laughlin China

Banner credit: Tea Time, Jason Meredith on Flickr
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