By Kirsti Scott
If you’ve ever picked up a piece of sea glass that was a beautiful purple color in the sun but seemed to have changed into a soft blue by the time you got home, you may have found a piece of neodymium sea glass.
Neodymium glass was produced throughout the world in the early 20th century, after Alexandrite crystals were discovered in 1885 and neodymium oxide (Nd2O3) was used to colorize glass. Leo Moser of Moser Glass was the first to develop the commercial use of neodymium in glass. He worked with scientists from Germany and England in the 1920s to perfect his process. Glass manufacturers from Czechoslovakia, Italy, Spain, England, and the U.S. followed suit, adding the compound to art glass, tableware, jewelry, and other items to take advantage of its color-changing properties.
The name neodymium is derived from the Greek words neos (νέος), new, and didymos (διδύµος), twin. Neodymium glass is dichroic, which means it shows as two different colors, depending on the type of light shining through it. In sunlight, neodymium glass looks lavender, and in fluorescent light it looks blue.
Different manufacturers had different names for neodymium glass. Moser Glassworks, A. H. Heisey & Company, Boyd’s Crystal Art Glass, Thomas Webb & Sons, and Morgantown Glass Works named theirs Alexandrite, after Russian tsar Alexander II who reigned during the time when the crystals were first identified. The Fostoria Glass Company, Steuben Glass Works, and Fenton Art Glass called their neodymium glass Wisteria; Tiffin Glass Company manufactured Twilight; The Cambridge Glass Company produced Heatherbloom; and Czech glass company ZBS produced the Luxodine line of neodymium glass. There were other manufacturers in the U.S., France, Scandinavia, Italy, and Spain, who made color-changing glass, both for tableware and sculptural pieces.
Costume jewelers such as Weiss Company, Kramer of New York, and others in the U.S. and Europe took advantage of the twin nature of neodymium glass, creating neodymium glass rhinestones that they used in their pieces.
Many of the early commercial makers of neodymium glass are now closed, and most made their neodymium pieces for a limited time, so neodymium glass and neodymium beach glass are scarce. For example, Cambridge’s Heatherbloom color was produced only from 1931-1935, and Morgantown advertised its Alexandrite glass for sale only during 1930.
Those who still use neodymium oxide to dye glass rarely make mass-produced products, but instead make bowls, vases, and decorative pieces. Glass artist Dale Chihuly has used neodymium in several of his glass sculptures, chandeliers, and more. Other current neodymium glassmakers are in the Czech Republic, the U.S., and China.
Neodymium glass also has industrial and scientific uses. The same process that filters the light in decorative glass is useful in lasers, welding and glassblowing goggles, astronomical filters, photographic filters, car rear view mirrors, and more. Neodymium glass is used in incandescent light bulbs to filter out yellow light for a bluer, bright-white color.
Sunlight is made up of relatively equal parts of blue and violet light, whereas fluorescent light has more blue than violet. Neodymium glass is great at filtering out the reds and yellows and only letting the other colors come through. This means more violet ends up coming through in sunlight, giving the neodymium glass a purple appearance, and more blue shows through in fluorescent light, making the glass appear blue.
So where can you find neodymium sea glass? Because it is so rare, the most likely places are near old glassworks, glass art studios, and large-scale manufacturers of industrial neodymium glass. Understandably, most collectors who find neodymium beach glass are hesitant to reveal the locations of their beaches. But if you’re lucky, some day you may find one of these beautiful bright purple pieces that hide a secret blue side!
For more color-changing sea glass, read about ultraviolet sea glass ›