One of the most distinctive qualities of Koa wood is its natural shimmer – a play of light across the surface that transforms each piece from beautiful to extraordinary. This characteristic has long been treasured by both woodworkers and those fortunate enough to own Koa pieces.
While we all know that special glow when we see it. We’re going to put on our science hats and explore exactly what creates this mesmerizing effect. Fun fact: Both of us have science backgrounds!
The Science Behind the Shimmer
When light dances across a piece of Koa wood, it creates a mesmerizing display that Hawaiian artisans have treasured for generations. This signature shimmer, known as chatoyancy, isn’t just beautiful – it’s a fascinating interaction between light and the wood’s unique cellular structure.
At the microscopic level, Koa’s cells are arranged in a way that creates natural “mirrors” within the wood. These distinctive ribbons of cells run from the tree’s core to its bark, like spokes on a wheel, reflecting light differently depending on your viewing angle. It’s similar to how silk and cat’s eye gems shimmer, which is why chatoyancy is sometimes called “the cat’s eye effect.”
These natural ribbons serve an important purpose in the living tree – they’re actually pathways that move nutrients between the inner and outer layers. In Koa, these essential cellular highways just happen to be arranged in a way that creates this spectacular visual effect.
The Influence of the Cut
The depth of this shimmer is influenced by how the wood is cut. Quarter-sawn Koa, where the growth rings meet the board’s face at a 60-90 degree angle, typically displays the most dramatic light play. This cutting technique exposes more of these cellular ribbons, creating those signature bands of light that seem to shift and move as you walk around a piece.
Koa’s Unique Growing Conditions
What makes Koa particularly special is how its growing conditions enhance this effect. Hawaii’s unique climate and volcanic soils create stress patterns in the wood as it grows, leading to what artisans call “curly” or “figured” Koa. These natural stress patterns create additional layers of shimmer, almost like waves in the wood’s surface.
Every Koa tree develops its own unique cellular pattern, which is why no two pieces are exactly alike. Factors like the tree’s age, growing elevation, and exposure to wind all influence how these cellular structures develop.
This is why we and other experienced craftsmen spend so much time studying each piece of wood we have – we’re looking for how to best showcase where these natural elements have combined to create exceptional figuring and shimmer.
Koa Wood’s Natural Beauty
Understanding the science behind Koa’s shimmer helps us appreciate why these pieces are more than just furniture or decorative items – they’re natural works of art, where beauty is quite literally built into their cellular structure.
Note: The featured image above is Big Island Engraving’s Handcrafted Koa Wood Calabash Bowl #110
