The Rationalist (Slate/Dark Gray)
The Rationalist (Slate/Dark Gray)
The Rationalist (Slate/Dark Gray)
The Rationalist (Slate/Dark Gray)
The Rationalist (Slate/Dark Gray)
The Rationalist (Slate/Dark Gray)
The Rationalist (Slate/Dark Gray)
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The Rationalist

Slate/Dark Gray

Real slate shimmers differently on The Rationalist – but guaranteed protection against UV radiation.

169,00 €
169,00 €  €
Tax included.

Made from genuine natural materials, with unique variations in color and texture.
Delivery in 2–5 business days
  • Free shipping including tracking

    Our customers benefit from free and fast shipping. More information here >

  • 24-month HOLZKERN warranty: repair or replacement

    Within the first 24 months, we will deal with problems that arise during normal use. LinkFind out more >

  • Free returns till January 31, 2027 | Club Account

    So you can shop for your Christmas gifts with no risk at all, we’re extending our return period until January 31, 2027. Club membership is 100% free—members receive a prepaid return label at no additional cost. Even without an account, you can return items until January 31, 2027; a small label fee applies.

Description

Clear thoughts start with a clear view.

Real walnut wood and slate develop their very own character in sunlight and make The Rationalist your naturally strong companion for bright days.

Thanks to flexible earpieces made of real wood and soft nose pads, your glasses also adapt to your individual face shape — for a comfortable fit all day long.

Find the patron saint for your summer now and enjoy every ray of sunshine with relaxed, alert eyes.

Safe protection guaranteed. Each pair of glasses is a unique piece from nature
The Rationalist
Slate/Dark Grey
Title: Default Title
169,00 €
169,00 €  €
No two pieces are the same
Over 2 million customers worldwide
Genuine natural materials
UV 400

Core features

Slate

Slate is formed deep inside the Earth, where immense pressure creates layers and compacts the rock over millions of years. Its dark, matte surface appears calm yet powerful – almost like a testament to the history of the Earth. In our unique pieces, slate represents the incredible tranquillity of the darkest depths and the power of time, a reminder of true strength and stability every day.

UV 400

Whether you’re on the beach, in the city or snowboarding on the mountain tops, with your Holzkern sunglasses you are always optimally protected. Sunglasses with UV 400 protection prevent all UV rays with wavelengths between 280 to 400 nanometres from reaching your eyes. With these kinds of sunglasses, all ultraviolet A, B and C rays that are dangerous for the eye are blocked.

Adjustable temple ends

Exceptionally comfortable to wear, custom-made for you. With a little care, the temple ends of these glasses can be adjusted to your individual face shape, ensuring an optimal fit. As they are made of real wood, you should always handle with the utmost care. To make adjustment easier, you can warm them up slightly, either with your fingertips or carefully with a hairdryer.

THE ART OF THE TRADE

Where nature meets craftsmanship

Every HOLZKERN piece begins with genuine natural materials from the forests, mountains, and oceans of our planet. With precision, experience, and innovative technology, we preserve nature's unique character and make it wearable every day. The result: accessories that are as individual as you are and remind you of your uniqueness for years to come.

Here’s what happens after you place your order

Strict quality control

Before it is packaged and shipped, each piece is individually inspected to ensure that it truly meets our high quality standards.

Secure Packaging

If it passes the test, we’ll package it carefully, securely, and as plastic-free as possible. We include tools and replacement links with our watches and Bandlets, so you can adjust your product to achieve the right size right away at home.

100% satisfied or your money back

Just a few days later, you’ll be thrilled to find your package waiting on your doorstep! Unpack it quickly and try it on—you can test your items for 24 days and simply send them back if you don’t like them.

We’re here for you

If you have any questions or issues, you can reach us via our service form. No waiting on hold or automated responses—our customer support team consists of 15 employees who are always committed to ensuring your satisfaction.

“With Holzkern I always want to express my love for nature and have set myself the goal of creating the perfect piece of nature for everyone.”

Elias Ferihumer

Founder of Holzkern