Hold a piece of dichroic glass up to the light, and you will see something remarkable. The color shifts from rich blue to fiery gold to deep magenta, changing with the smallest tilt of your wrist. This is not a trick of the eye. It is the result of thin-film optics, a technology with roots that stretch back to 4th-century Rome and extend forward through NASA materials research. Dichroic glass is made by applying 30 to 50 micro-thin layers of metal oxides onto a glass base, creating a surface that transmits some wavelengths of light and reflects others. The result is a material that seems alive with color.
At ArtGlassSupplies.com, we stock more dichroic glass than anyone else in the world. We carry both COE90 and COE96 varieties in solid colors, patterns like Aurora Borealis, etched textures, frit, and scrap packs. Whether you make jewelry, fused glass bowls, or stained glass panels. Understanding what dichroic glass is and how to work with it opens up a new range of creative possibilities.
What Is Dichroic Glass?
Dichroic glass is glass that displays two or more different colors depending on the lighting conditions and the angle from which you view it. The word comes from the Greek dichroos, meaning two-colored. When light strikes the surface, some wavelengths pass through while others are reflected. This creates the shifting, iridescent effect that makes dichroic glass so sought after in jewelry, fused glass, and stained glass work.
The Science Behind the Color Shift
The color-shifting property is the result of thin-film optics. Multiple ultra-thin layers of transparent metal oxides, including titanium, chromium, aluminum, zirconium, magnesium, and silica, are deposited onto the glass. Each layer is only a few billionths of a meter thick. The total coating, though it may contain 30 to 50 individual layers, measures just 30 to 35 millionths of an inch, or about 760 to 890 nanometers.
These layers act like a prism. They split white light into its component colors, transmitting some and reflecting others. The specific colors you see depend on the exact thickness and arrangement of the layers. That is why a single piece can shift from green to purple to gold as you move it under a light.
An Ancient Technique with Modern Roots
The oldest known example of dichroic glass is the Lycurgus Cup, a 4th-century Roman artifact housed in the British Museum. The cup appears green when lit from the front and red when lit from behind. Ancient glassmakers achieved this effect by adding tiny particles of colloidal gold and silver to the glass itself, an extraordinary technical achievement for its time.
Modern dichroic glass was developed through materials research conducted by NASA and its contractors, who needed dichroic filters for space applications. After NASA made the technology publicly available, glass artists and manufacturers adapted it for decorative use. Today, companies like CBS (Coatings by Sandberg) produce dichroic glass specifically for the art glass market, using the same vacuum deposition science refined during the space age.
Browse our full dichroic glass collection today and find the perfect pieces for your next project.
How Dichroic Coatings Are Made
Modern dichroic glass is manufactured using physical vapor deposition, a process that takes place inside a vacuum chamber. Here is how it works, step by step.
- Prepare the base glass. The process starts with a sheet of clear, black, or textured glass that will serve as the substrate. The base glass must be clean and free of contaminants. Manufacturers use standard fusible glass in COE90 (Bullseye-compatible) or COE96 (Oceanside/Spectrum-compatible) so artists can integrate dichroic pieces into their existing projects.
- Place the glass in a vacuum chamber. The prepared glass is loaded into a sealed chamber. All air is pumped out to create a near-perfect vacuum. This is essential because any gas molecules in the chamber would interfere with the coating process and produce uneven layers.
- Vaporize the coating materials. An electron beam gun fires a focused stream of high-energy electrons at solid pieces of quartz and metal oxides, including titanium, chromium, aluminum, and silica. The energy is intense enough to vaporize these materials instantly, turning them into a cloud of highly reactive vapor inside the chamber.
- Condense the vapor onto the glass. The vaporized particles travel through the vacuum and condense onto the surface of the glass, forming an ultra-thin crystal layer. The chamber rotates or moves the glass to ensure even coverage. Each layer is deposited one at a time, with the composition changing from layer to layer to produce the desired color effects.
- Build 30 to 50 layers. The process repeats, building layer upon layer, until the coating reaches the target thickness. The total coating ends up between 30 and 50 layers, yet the entire stack is only about 760 to 890 nanometers thick. To put that in perspective, a human hair is roughly 100 times thicker.
The result is a glass surface that reflects and transmits light selectively. Different manufacturers specialize in different effects. CBS (Coatings by Sandberg), a premier partner of ArtGlassSupplies.com, produces both solid color dichroic and patterned variations such as Aurora Borealis, Corkscrew, and Stripes, as well as etched dichroic with unique surface textures.
Understanding COE Compatibility for Dichroic Glass
When you fuse two pieces of glass together in a kiln, they expand as they heat up and contract as they cool down. The rate at which a glass expands and contracts is called its Coefficient of Expansion, or COE. If two pieces of glass have different COE values, they will expand and contract at different rates. The result is stress that leads to cracking, sometimes immediately and sometimes weeks or months later.
This is why COE compatibility is the single most important rule in glass fusing. As fusing educators emphasize, every single project is destined to fail if you mix glass types with different expansion rates. It is impossible to tell the difference just by looking, so you must rely on manufacturer labeling.
COE90 vs. COE96: What You Need to Know
The two dominant standards in fusible glass are COE90 and COE96. COE90 glass is manufactured primarily by Bullseye Glass and is the standard for Bullseye-compatible dichroic glass from CBS. COE96 glass is used by Oceanside Glass, Spectrum, and other manufacturers. ArtGlassSupplies.com stocks dichroic glass in both COE systems.
Dichroic glass is always manufactured on a specific base glass type. When you buy a dichroic piece, it has a stated COE rating. You must match that rating to the other glass in your project. Using a COE90 dichroic piece with COE96 base glass will produce cracking, even if the dichroic layer itself is thin. The entire piece is still subject to the expansion stress.
How to Choose the Right COE
If you already work with Bullseye glass or other COE90 fusible sheet, buy COE90 dichroic glass. If you use Oceanside, Spectrum, or other COE96 brands, choose COE96 dichroic glass. Never mix the two systems in a single project.
When in doubt, run a small test fire. Place a sample of your dichroic piece next to a sample of your base glass and fire them together using your planned schedule. Let the test piece cool completely, then inspect it under bright light for cracks or stress lines. A polarizing filter can make hairline stress fractures visible. This simple test can save hours of work and an entire project.
Solid Color vs. Patterned Dichroic: What’s the Difference?
Dichroic glass comes in two broad categories: solid color and patterned. Each has its own visual character and works best for different types of projects. Understanding the difference helps you choose the right piece for your design.
| Feature | Solid Color Dichroic | Patterned Dichroic |
|---|---|---|
| Appearance | Uniform, consistent color shift across the entire piece | Complex designs, flowing lines, repeated motifs, or etched textures |
| Popular patterns | N/A | Aurora Borealis, Corkscrew, Stripes, Pixie Stix, Herringbone |
| Best for | Beginners, simple fusing, jewelry with clean lines, projects needing even color | Statement pieces, advanced designs, artists who want one-of-a-kind effects |
| Availability | COE90 and COE96, on clear and black base glass | COE90 and COE96, including etched and textured surfaces |
| Typical price range | $6.68 to $9.96 per piece on sale (25% off) | $7.47 to $10.96 per piece on sale (25% off) |
Solid Color Dichroic
Solid color dichroic is the best starting point for artists new to the material. The coating is uniform across the surface, so the color shift is predictable and consistent. This makes it ideal for jewelry projects like cabochons and pendants, where you want a clean, polished look. Solid color dichroic is available on clear and black base glass in both COE90 and COE96.
Patterned and Etched Dichroic
Patterned dichroic adds visual complexity. Patterns like Aurora Borealis create flowing bands of shifting color, while Corkscrew and Stripes produce linear designs. Etched dichroic has a matte, textured surface that scatters light differently, creating a softer, more diffused color effect. These varieties are excellent for focal pieces in fused glass bowls, art panels, and stained glass windows. They command a slight premium in price but produce results that solid color cannot match.
Browse the full selection of COE90 dichroic glass and COE96 dichroic glass to compare options for your next project.
Stunning Projects You Can Make with Dichroic Glass
Dichroic glass is one of the most versatile materials in the glass artist’s studio. Its shifting colors and brilliant reflections make it a natural choice for projects that demand attention. Here are some of the most popular ways artists use it.
Fused Glass Jewelry
Jewelry is by far the most common application for dichroic glass. Pendants, earrings, cabochons, and rings all benefit from the color-shifting effect. The process is straightforward: cut a small dichroic piece, place it on a clear glass base, cap it with a thin clear layer, and fire. The clear cap protects the coating and gives the piece a glossy, gem-like depth. Dichroic jewelry is popular at art fairs and craft shows because it catches light from every angle. For detailed techniques, see our dichroic glass jewelry guide.
Fused Glass Art and Functional Pieces
Dichroic glass works beautifully in larger fused pieces. Bowls, plates, coasters, decorative tiles, and wall art all gain visual interest from the shifting colors. Artists often use dichroic as a focal accent in the center of a clear or opaque base, surrounded by compatible fusible glass in coordinating colors. The contrast between the metallic, light-responsive dichroic and the soft, matte opalescent glass creates a striking effect. Patterned dichroic, such as Aurora Borealis or etched textures, works especially well as the centerpiece of a larger fused composition.
Stained Glass Accents
Stained glass artists also use dichroic glass, though less commonly than fusers. The material works well as an accent in stained glass panels, where its reflective quality adds a dynamic element to the static composition. Because dichroic glass may be more expensive, it is typically reserved for focal sections or smaller decorative elements rather than full panels. COE compatibility is less of a concern in copper foil or lead came stained glass construction since the pieces are not fused together and do not go through a kiln firing.
Mixed Media and Sculptural Work
Beyond these standard applications, dichroic glass appears in mixed-media art, mosaic projects, and sculptural installations. Artists combine dichroic scraps with resin, set them in metal findings, or mount them in light boxes that emphasize the color shift. Dichroic frit and noodles add sparkle to cast glass pieces. For artists who want to experiment without buying full sheets, ArtGlassSupplies.com offers dichroic scrap packs, frit, and stringers in both COE90 and COE96.
Tips for Working with Dichroic Glass
Working with dichroic glass is an exciting way to add bright color to your art. To get the best results, you must follow some basic steps. Proper prep and care will keep your pieces safe.
Cutting and scoring techniques
Always score your sheets from the uncoated back side. The color coating is thin and easy to damage. It has 30 to 50 layers of metal oxides. Yet, the total depth is only about 30 to 35 millionths of an inch. This is about 760 to 890 nanometers thick.
Cutting from the coated face can cause the metal layer to scratch or tear. When you score the glass, use a clean cutter and apply even force. A light oil on your tool can help you get a smooth break. Run your pliers along the score line to snap the glass with ease.
Do not use a grinder on the coated side of your glass. The fast spin of a grinding wheel can peel the thin metal layers right off the surface. If you must grind the edges to shape your pieces, do so with care. Work slowly and keep the glass wet to prevent chipping and wear.
Assembling and cleaning your glass
You must clean your glass before you place it in the kiln. Oils from your hands can leave dull spots on the metallic surface. These spots do not go away after firing. Use a mild soap and warm water, or rub the glass with rubbing alcohol to clean it.
When you build your project, you need to hold the small pieces in place. You can use dabs of white glue to bond them. Use a tiny toothpick to apply the glue so you do not use too much. The glue dries clear and burns off in the kiln. It does not leave any marks or ash on your finished work.
Fusing and firing guidelines
Always fire your pieces with the color side facing up. If the coating faces the kiln shelf, it can stick and ruin the shelf or your art. To protect the thin metal layers, you can use a clear glass base. You can also cap your art with a clear sheet. This cap seals the shifting colors and gives your work a deep, glossy look.
Always run a test fire before you commit to a large project. Test fires help you see how the kiln heat affects your specific glass. If you plan to make wearable art, search for new jewelry project ideas to try. You can buy quality sheets of COE90 dichroic glass to make your own pieces. A quick test ensures your colors stay bright and your glass does not crack.
Shop our world-class dichroic glass inventory for your next project.
Frequently Asked Questions
Why is dichroic glass so expensive?
The high price of dichroic glass comes from its complex making process. It needs high-tech vacuum chambers where metal oxides are heated to form a vapor. This precise method, developed from NASA-funded research, applies 30 to 50 micro-thin layers to the glass. The special tools and careful work make it a premium art supply.
Does dichroic glass fade over time?
No, dichroic glass will not fade, peel, or lose its color over time. The metal oxide layers are bonded to the glass at a molecular level inside a vacuum chamber. This makes the coating extremely durable and resistant to solar heat or weather. It can also withstand high kiln heat, so the brilliant colors remain bright and clear through multiple firings.
Can dichroic glass be fired multiple times?
Yes, you can fire dichroic glass multiple times in a kiln without damaging the color-shifting coat. The ultra-thin metal layers are highly heat-resistant and remain stable up to full fusing temperatures. However, you should avoid heating the glass too fast or holding it at high heat for too long. Capping the dichroic layer with clear glass can help protect the metal coating from devitrification.
How can you tell which side of dichroic glass is coated?
You can find the coated side of dichroic glass with a simple pencil test. Place the tip of a pencil directly onto the glass surface. If the pencil point meets its reflection with no gap, you are touching the coated side. If you see a small gap between the point and the reflection, you are touching the uncoated glass side.
Ready to Start Your Next Dichroic Glass Project?
Putting off your next glass art project means your new designs stay on the shelf, and you miss the chance to make bright art. Waiting to buy your glass also risks slow shipping that will push back your studio timeline, delay your work, and stall your sales. Buying your new COE glass today helps you get the right colors you need to start fusing great art by next week. You can read our guide on jewelry project ideas to plan your designs while we pack and ship your glass to your door. Our support staff is here Monday through Friday to help you choose the right sheet sizes and COE systems for your studio.
Ready to create? Browse our full dichroic glass collection now.