Mother of Pearl Glass Patterns

by Stu Horn

Although Mother of Pearl (often abbreviated MOP) is the name most often used in modern times in this country for art-glass with a pattern formed by trapped air, other terms that have been used are Air Trap, Pearl Ware and Pearl Satin Ware. Although this technique was reportedly used by the Venetians, it was first patented by Benjamin Richardson, in England, in 1857-58. In the United States,  Joseph Webb of the Phoenix Glass works was favored with a manufacturing patent for a similar product in 1886.

To create MOP glass, molten glass is blown into a mold with the pattern defined by projections. This glass is then cased - thus trapping the air internally and creating a lasting and attractive pattern. I am sure most collectors have seen and perhaps acquired the two most common of the MOP patterns - Diamond Quilted and Herringbone. The thought for this article was to identify and illustrate both the common and the less common patterns. In doing so, I have included example photographs from my collection and the collections of others in the on line Rose Bowl Collectors Group.

While there is a fair amount of variation in these patterns between manufacturers, and because of the expansion of the glass when being formed into its final shape, I have tried to show examples that are representative of the pattern in general. Significant variations in size, proportions and spacing will be found. Two possible pattern variations, Muslin (vs. Raindrop) and Herringbone Variant, are included as they are often described separately by collectors.
I have tried to use common names for these patterns, as used by collectors and as appearing in the literature. Where I have not been able to identify a name, I have made up a descriptive name which is shown in quotation marks. If anyone knows of a more proper name for these - - please let me know and I will add it to this page.

Of course, the number of MOP patterns is open ended - since anyone with some artistic skill and the means to make a glass mold could design one. Hopefully this article will help you identify the ones that are available in antique art-glass forms such as the rose bowl.

I welcome comments on these designs as well as patterns that I may have missed. Please Email me at with your thoughts.

Many thanks to Rose Bowl Group members who have kindly given me permission to use their pictures and a special thanks to the Fairy Lamp Club for hosting this website.

Diamond Quilted
Many variations exist in the shape of the diamonds, spacing etc. Occurs in Murano reproduction pieces also.

aka "Ribbonette"
or "Zig Zag"
Angularity, spacing and size differences are common. Also found in Murano reproduction pieces.

Ribbon Stripe
Seen vertical and somewhat swirled.

Some pieces have a more specific name such as the Pompeian Swirl of Stevens & Williams. Found in right and left hand versions.

"Murano Drape"
Similar to above but horizontal lines shaped like a bracket symbol. Found in Murano reproduction pieces.

Peacock Eye
Two semicircles over the round eye.

"Flower in Diamond"

Thumbprint like circular drops.

Resembles Stevens & Williams Jewel Glass pattern with addition of air traps.

Resembling the branches of a small stream? Possibly attributed to Thomas Webb & Sons.

aka Watered Silk
Graduated somewhat erratic concentric rings

Maltese Cross

"Open Concentric Diamonds"

Rounded hobnail like projections containing the trapped air.

Polka Dot – Dots in diamonds.
Courtesy of Louis St. Aubin
Brookside Art Glass

Herringbone Variant
Similar to Herringbone but discontinuous.
Courtesy of Louis St. Aubin
Brookside Art Glass

Muslin - Dotted Swiss
A pattern of this type was also made by Fenton in the 1960's called "Bubble Optic."
Courtesy of Louis St. Aubin
Brookside Art Glass

A very attractive pattern but I have no idea of its correct name.

Sagging horizontal lines with vertical separations.

Octopus or Federzeichnung
Serpentine projections somewhat resembling octopus arms.

Spider Web
Everything but the spider. Because of the large size of the overall pattern – only found on large relatively flat pieces such as Brides Baskets.

Possibly associated with Mount Washington.


Plus Marks and Drops With Open Centers
Associated with Steuben

A series of concentric ever larger star shapes.  Thought to be made by Phoenix Glass Company

Thought to be made by Phoenix Glass Company.
Courtesy Lee Marple

Swirled Ribbed Drops
Some similarity to other "Drop" patterns but specific to Hobbs Brockunier and Company
Courtesy Tom Bredehoft.

Pulled Loops
Courtesy Tom Bredehoft.

Similarities to Moiré but without so many closed elements.
Courtesy Bob McCleskey.

Peacock Eye Variant
A variant, somewhat distorted, has also been identified with just two arcs or sometimes with only one arc and enlarged "eye."

Random #3 - No name
Gives the impression of a fern-like random pattern.

Random #1 - No name
Similar to Rivulet but enough differences to merit a separate identification.
Courtesy Bill Stoetzel.

Random #2 - No name
Also similar to Rivulet - - seems to be more of a raised effect.