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 firstname.lastname@example.org 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.