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Vintage Mosser Cats, in particular the Mosser Sitting Cat, have been enjoying new found popularity on social media and among collectors, both old and new. And little wonder – these charming kitties were made in well over 100 different colors and finishes and are equally beautiful on a shelf or table, in a curio cabinet or on a sunny window sill. There is a lot of detail in the fur, a tail curled around the left of the cat, and a curious expression as the cat looks up over their left shoulder. Best of all, at 3″ high with a base that is just 1 5/8″ x 1 1/4″, they don’t take up much space. Like potato chips, you can’t have just one!
With prices soaring, do you know what you’re buying? And is it a good deal? Bookmark this guide and refer to it next time you’re shopping on eBay, Etsy or at your local thrift shop!
Table of Contents
Is it Genuine? Finding and Reading Mosser Glass Marks
Mosser Cat Colors
Iridized (“Carnival”) and Satin Finishes
Slag and Opalescence in Mosser Sitting Cats
UV Reactive Mosser Cats
Manufacturing Quirks
How Old Is It?
Mosser Cats made for other glass sellers
What to Look For
Caring for your Mosser Cat Figurines
Related & Similar Collectibles
Is it Genuine? Finding and Reading Mosser Glass Marks
While there haven’t been any reports of “counterfeit” Mosser cats flooding the markets, it’s always good practice to look for a manufacturer’s mark. Mosser sitting cats are always marked in one or more ways:
- An “M” on the back of the cat, at the base of the tail. With the exception of a few very early pieces, all of the original sitting cats have this mark, however it blends in with the fur detail and can be difficult to see.
- A large incised “M” or a smaller “M” in a circle, hand stamped on the plunger mark on the base of the piece. This was used up until around the mid 1980s.
- Some Mosser cats have a radiating “star” mark on the base. This was not used past the mid 80’s. It really doesn’t make the piece more valuable, but it is an oddity to note if you come across it
- On newer cats the bottom of the piece, including the plunger mark in the middle, is neatly finished.
- Newer cats (2000- 2007) may still have an oval Mosser label on them (shown on a collie in the bottom photo).
- Cats made as special orders in 2023 or later will have an “M” inside the outline of the state of a Ohio on the lower back in the center – a little bit to the right of where the old mark was.
[Finding the Mosser mark on Mosser cats ]
Mosser Cat Colors
The sitting cats were manufactured in every color of the rainbow, including beautiful slag combos. Unfortunately, Mosser did not keep good records of the colors during the years the sitting cats were being made. All they have is a typewritten and handwritten list of colors (and some dates) in a little notebook, with no accompanying descriptions. Adding to the confusion, some of Mosser’s other items were manufactured in the same colors but sold with different names, and collectors and even some dealers made up their own names for certain variations! Needless to say, there is some controversy among collectors as to the actual names of some colors! If you can get your hands on a Mosser catalog especially from the later years, there are pictures of them in there, but these not easy to find. I’ve done my best to describe and illustrate them on the “Mosser Sitting Cat Colors” page and in our Gallery photos.
Newly listed Mosser glass cats on eBay
Iridized (“Carnival”) and Satin (“Frosted”) Finishes and Luster
In addition to the normal “shiny” glass, Mosser sitting cats were made with two additional surface finishes:
- Iridized or “Carnival” – A metallic rainbow effect on the surface of the piece. The cat is removed from the mould and treated with a mist of metallic oxides. As the piece cools, these create an iridescent appearance on the surface. [Learn more about carnival glass]
- Satin or “Frosted” – A matte finish on the surface of the cat. The piece is removed from the mould and either treated with a very fine mist of hydrofluoric acid or sandblasted – which evenly etches the surface of the item. A lot of these Mosser cats were also made with a satin finish. [Learn more about satin glass]
- What is “Luster?” – According to the Corning Museum of Glass, luster is “A shiny metallic effect made by painting the surface with metallic oxides that have been dissolved in acid and mixed with an oily medium.” There are only two luster colors in the sitting cats: Royal luster (purple) and Opal luster (off-white.)
All of these are surface finishes – added after the item is removed from the mould. They are not a special type of the glass itself.
Slag and Opalescence in Mosser Sitting Cats
Slag and opalescence (aka “opal”) are names for specific types of glass:
- Slag is a combination of different glass colors – usually swirled together.
- Opalescence (not to be confused with iridescence) is characterized by white areas on the edges of the piece. This is caused by putting the piece briefly back into the furnace a second time. Certain properties of the glass used will make it turn white when reheated.
On the sitting cats, opalescence is typically seen on the ears, feet and tail, and sometimes on the face. [Learn more about opalescent glass]
UV Reactivity: Mosser Cats That Glow!
Some glass pieces manufactured by Mosser contain additives that are UV reactive – they glow different colors under a UV (“black”) light. These additives can stabilize glass colors, enhance a color and/or improve the appearance of glass with certain impurities. They may alter the apparent color some pieces in sunlight because of the sun’s UV rays. Popular additives include:
- Uranium oxide – aka depleted uranium, glows bright green under UV light, gives the piece a greenish cast in sunlight. The more uranium it has, the brighter it glows. Vaseline and Custard glass are familiar examples of glass containing uranium oxide. Uranium oxide can no longer be purchased for use in glass, making uranium glass highly collectible.
[Learn how to identify vaseline glass.] - Cadmium – glass containing cadmium typically glows yellow under UV light, but can range from yellow and orange to pink and red, depending on other uv reactive additives.
- Manganese – Manganese dioxide was added to glass to neutrolize color impurities (such as iron) and/or to stabilize the glass color over time. Manganese glows green under 365nm UV light, but the visible color is modified by the color of the glass itself.
- Selenium – Glows neon pink or red under a black light. Selenium was used in red glass, often with cadmium.
[ Learn more about Additives and UV Reactivity in Mosser Cats ]
Looking for a bargain? Here are the lowest priced Mosser cats on eBay
Manufacturing Quirks
- On some of the early cats (i.e. the ones marked with an “M” on the base), there is either an extra lump of glass or a sharp area at the top of the right ear. This was an issue with the mould and removing the cats from the mould – it was fixed and ears are smooth in later years.
- Until the late 80’s or early 90’s, the plunger mark (where the glass was injected into the mould) on the base of the cat was not polished or smoothed. Sometimes there are sharp spots – watch your fingers!
- “Droopy” or “leaning” cats – Every now and then you’ll come across a cat that “droops” or “leans” farther to their right than normal. This happens in the lehr during the annealing process and is fairly common. Compare the slightly “droopy” lemon-lime swirl below on the left to the “normal” cat on the right.
How Old is It?
Exact age of these cats can be difficult to determine.
- First place to look is on our color list – dates shown in the list were taken from Mosser’s own notes.
- The “M” mark on the bottom was not used past the mid 80’s.
- Cats with a very neatly rounded and polished plunger mark (the place where the plunger pushed glass into the mould) on the base are probably newer.
- MOST (but not all) of the slag combinations were made in the early years – up through the 1980’s. Chemical incompatibility of some glasses in the slags gave them a tendency to crack during production, making them more expensive for Mosser to produce. For this reason, they opted to produce mainly single color pieces in later years and in newer pieces like the Fluffy Cat (“Kitty”).
Exceptions include Purple Swirl and Butterscotch slag.
2002-2007
In the final 5 years that the sitting cat was produced, Mosser manufactured them for the most part in the following group of colors:
Milk
Jadeite
Hunter Green
Hunter Green Carnival
Crystal
Crystal Carnival
Rose
Red
Cranberry Ice
Vaseline
Cobalt
2023 – Sitting Cat Redux
To meet the huge increase in market demand for these cats in 2023, several vendors placed special orders with Mosser to rerun the sitting cat figurines. These were made in limited numbers using the original Mosser mould. These are all marked with the current Mosser mark – an “M” inside the outline of the state of Ohio.
Colors included:
Georgia Blue (shiny and carnival) – Special order by Vintage Farmhouse Treasures for the Mosser Cat Central group on Facebook
Marble (shiny and carnival) – Special order by Rosso Wholesale Glass
Light Lavender (Error color) – shiny and satin. This color was a mistake in mixing a batch of Crown Tuscan for another product. Rosso Glass paid to have this glass used for a special order run of the sitting cats.
Cobalt (shiny and carnival) – Special order for Miriam’s Timeless Treasures. Some were later sandblasted to a satin finish.
Titanium (shiny, satin and carnival) – dark translucent gray, similar to smoke. Special order for Rosso Wholesale Glass
Black and Black Carnival
Airbrushed over Crystal Carnival and other reissued colors – various colors and some multicolored – decorated and sold by Rosso Glass
Airbrushed and sand carved – various, decorated and sold by Rosso Glass
Midnight Blue and Midnight Blue “Opalescent” – Not a true opalescent. This was a mixture of black and crystal – there is a lot of variety in color and opacity.
Kimberlite Blue – Shiny, satin, iridized and combination finishes
Buffett Blue – Named in honor of the late Jimmy Buffett, this is the same color as Aqua in the Mosser angels, or the vintage blue (though apparently with a little less colorant.)
Apple Green – like the vintage color. All 3 finishes, special order for Buckeye RBR
Hunter Green – New formula, somewhere between the old hunter and emerald.
Rose – Reissued in all 3 finishes as a special order.
Crown Tuscan – Glossy and carnival finish, run for Max Iverson. The glossy is very similar to the vintage Heirloom Pink, which was sold as “Crown Tuscan” in their catalog – if you’re buying a vintage heirloom pink online, be sure to check the older mark on the back. “Heirloom Pink” was not run with an iridized finish.
Milk White – Glossy, satin and iridized finishes. Special order for Miriam’s Timeless Treasures.
See the Mosser Sitting Cats Colors page for a complete list and details.
Mosser Cats made for other glass sellers
During their main production years, Mosser made some cats as special orders for other glass sellers.
- Alexandrite cats (and some other animal figurines) were manufactured in a limited number in 2003 for sale by Collector’s Addition. Alexandrite is a dichroic glass (it appears to be different colors depending on the type of light) due to neodynium in the glass. They were made in shiny, carnival and satin finishes.
- Rubina – was a special order for a customer (unknown).
- Mosser made some cats for Rosso Glass. Rosso sold some of them as-is and others with sand carved and/or airbrushed decoration done by Rosso. (Rosso had a similar arrangement with Fenton glass.) Un-decorated colors included Royal Plum Opalescent (collies only?), Butterscotch Slag and Candy Corn.
What to Look For
A checklist for buying Mosser cats.
- Check around the edges for cracks and chips. Those glass feet and ears are the most easily damaged.
- Know the terminology and what it means. I’ve seen uninformed sellers who just copy listings from successful sales without changing much. Is it really “opalescent” or should it say “iridescent?” Is it a “slag” or just “opaque?”
- Look for marks – Look at the mark on the back and check to see if there is a mark on the bottom. This will help identify colors and give you a clue as to when the piece was made. Very important, given the reissued colors and airbrushed cats!
- Examine the photos carefully – Look at them full size. If you’re ambitious, pop them into photo editing software to correct obvious color shifts and sharpen detail. With a little practice you will get very good at deceiphering bad photos!
- UV reactive cats are very much in demand and commanding premium prices. If the buyer claims that the item “glows” expect to see photos of the cat under UV light. Ask for photos if there are none in the listing. If you’re in a thrift shop or flea market, you may want to bring a small “black light” flashlight with you.
- The term “RARE” is overused – Since it’s a retired item, certain colors / finishes of the sitting cats ARE genuinely hard to find – especially the older colors. That said, some sellers just add the word to every listing title to hype the auction. Look at previous sales. If 10 items of the same color sold in the last 2 months, it probably isn’t “rare.”
- Online bidding – in a “bidding war” it’s easy to get caught up in the moment and spend way more than you were planning on spending! Start with an idea of how much the item is worth TO YOU and the maximum you’re willing to spend on it.
- Last but not least: As with all collectibles, buy what you love!
Check out recent Mosser cat sales and prices on eBay
Caring for your Mosser Cat Figurines
Mosser cats are fairly solid and sturdy, but there are still some precautions you can take to preserve your collection:
- Pieces with iridized and satin (frosted) surface finishes – are susceptible to wear from excessive handling.
- Satin glass can scratch easily and scratches are very noticeable on some colors.
- If you have your Mosser cats out in the open on a shelf, mantle or table, museum putty (aka Quakehold) is your friend! Especially if you have real cats!
- Place pieces far enough apart that they are not touching – easy to cause little scratches and dings if they’re too close together.
- Dust regularly – Yes it’s a pain, but dust can leave tiny scratches too.
- If necessary, clean with warm water and a mild dish soap.
- Avoid extremes of temperature – Extreme cold or heat, or going from one to the other can crack glass. If you get a new cat delivered during very cold or very hot weather let it sit for a while in its box indoors before unpacking it.
- If you’re shipping them – Be generous with the bubble wrap (they’re small, it doesn’t take much) and tape it – especially if you are shipping multiple cats in the same box.
- If one you absolutely LOVE gets broken – Accidents happen. I’ve made acceptable repairs using clear 2-part epoxy. Use a THIN layer to keep the epoxy from taking up noticeable space between the pieces being glued.
Related & Similar Collectibles
Mosser Glass Sitting Cat Plates
Between 1980 and 1988 Mosser manufactured 3.5″ miniature “cup plates” with a raised image of the sitting cat figurine. It was sold as Mosser #155. Mosser’s notebook lists 14 colors for these plates, I have run across a few additional colors not listed in their notes. Crystal (clear) is the easiest to find. These used to run $10-$40, but prices have increased along with the cats themselves. Still, a plate in any given color will cost you less than a sitting cat in the same color.
Mosser sitting cat plates on eBay
Boyd Art Glass “Miss Cotton the Kitten”
Another small art-glass cat collectible. Miss Cotton measures just 2 1/2″ tall with a base that is 1 3/4″ x 1 1/8″. Boyd’s founder Bernard C. Boyd was a master color technician, and Boyd kittens were made in a mind boggling array of colors – clear and slag, some with satin finishes – and made copious use of UV reactive additives. Increased attention to the Mosser cats has increased demand for these, and prices have climbed considerably since 2022.
Boyd Glass kittens on eBay
Don’t miss out – Mosser cats ending soon on eBay!