GOBLOW // JOURNAL
The GoBlow Rainbow — Understanding Titanium Oxide Colour
The colour you can't paint on
Rainbow titanium isn't a coating. It isn't a dye, a pigment, or a film sprayed onto the surface. The colour is the surface — grown into the metal itself by controlled heat. That's why it doesn't fade, doesn't chip, and doesn't sit on top of the steel like paint waiting to wear off.
Built for this? See compare all 5 finishes.
The GoBlow Rainbow is the most technically interesting finish in the range, and it's the one most people misunderstand. Here's what's actually happening.
TiO2, not PVD
Black, Gold and Rose Gold GoBlow finishes are PVD — physical vapour deposition. A target metal is vaporised inside a vacuum chamber and bonded to the steel at the molecular level. It's a real coating, applied to the surface.
Rainbow is different. There is no coating. The titanium-oxide layer (TiO2) is grown directly out of the metal by heating it to a precise temperature in open air. Oxygen reacts with the surface, the oxide layer forms, and the thickness of that oxide layer is what produces the colour you see.
No paint. No plating. No vacuum chamber. Just controlled heat and chemistry.
Why it looks like that — the physics
The colours you see on a Rainbow pendant aren't actually colours in the way most things are coloured. They're light interference. Same physics as a soap bubble, an oil slick on a wet road, or the underside of a beetle's wing.
Light hits the oxide layer and reflects off two surfaces at once: the top of the oxide and the metal underneath. Those two reflections interfere with each other. Some wavelengths cancel out, some reinforce. The wavelength that survives the interference is the colour you see.
- Thin oxide layer (around 30nm) — straw gold
- Slightly thicker — bronze, then violet
- Thicker again — deep blue, then teal, then green
- Thicker still — magenta, then pink, then a second cycle of colours
Different oxide thicknesses give different colours. The Rainbow finish runs through a band of those thicknesses across the surface, which is why you see the spectrum on a single piece.
Why it shifts in different light
Pick up a Rainbow pendant in daylight, then move it under a warm bar light, then a cool LED. It looks like three different pieces. That's not a defect — it's the entire point.
The interference effect depends on the wavelengths of light hitting the surface and the angle they hit at. Change the light source or the viewing angle and the dominant colour shifts. Daylight reads cooler — more blues and greens dominate. Warm bar lighting pulls the magentas and golds forward. LED uplighting at a festival can flip it again.
Most jewellery looks the same in every photo. Rainbow doesn't. It looks different every time someone shoots it, and different again to the next person standing two feet away.
Why it doesn't fade
Pigments fade because they're chemicals that break down — UV light, oxidation, abrasion. Coatings wear because they're physical layers sitting on top of a substrate, and friction eventually takes them off.
The Rainbow colour is neither. The oxide layer is the metal — chemically bonded, structurally part of the surface. There's no pigment to break down and no coating to wear through. As long as the oxide layer stays intact, the colour stays. The oxide is harder than the steel underneath and chemically stable in air.
The colour is in the physics, not in a layer of paint. That's why it lasts.
The most technically interesting piece in the range
Steel is honest engineering. Black is precise PVD. Gold and Rose Gold are PVD with a warmer signature. Rainbow is a different kind of object — a piece where the colour is a side effect of the physics of light, not something applied to the metal.
It's the finish that rewards close attention. In a flat photo it looks like one thing. In your hand, under changing light, it's never the same twice.
Built for festivals and night events
Rainbow earns its place under coloured lighting. Festival stages run lasers, LED walls, UV, smoke. Nightclubs run uplights and strobes. Rooftop bars run warm-tungsten and harbour-blue. Rainbow reacts to all of it.
A Steel pendant looks the same on the dancefloor as it does on the train home. Rainbow doesn't. It picks up whatever's around it and throws it back. That's why the festival crowd gravitates to it — not because it's flashy, because it interacts with the environment in a way no plain finish can.
The piece that photographs differently every time
If you've seen four photos of the same Rainbow pendant and thought they were four different finishes, that's the finish working as intended. The angle changed. The light changed. The colour cycle shifted across the surface.
Most products have a single look that gets reproduced in every photo. Rainbow has a range. Owners end up with a camera roll of the same piece in twenty different colour states — daylight greens, indoor magentas, festival blues, bar-light golds.
It's the GoBlow piece you don't get tired of looking at, because you're not looking at the same thing twice.
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Continue reading: Goblow Steel Vs Black Vs Gold Vs Rose Gold Vs Rainbow Which Finish
Want both pieces together? The Carry Kit pairs the Pendant with Stacks.