Our Story

Pistachio shells are “ingenious.” They’ve been lauded for their extraordinary strength-to-weight ratio, achieved by a cellular structure researchers call a “holy grail of materials science.” In fact, they may one day be used to make shock-absorbing items like safety helmets. 

Admittedly, I didn’t know any of that around 2010 when I saved some discarded pistachio shells, bought a small drill, and began experimenting. I did know I loved turning the shells into sculptural earrings that were so lightweight I could barely feel them. (Lightweight earrings are generally considered to fall between 2 and 4 grams per earring; TACHIO’s earrings range from 0.4 to 1.3 grams per earring.)

Roughly fifteen years later, when I finally dusted off that drill and pulled out several bags of shells I’d been squirreling away, I approached the process with a renewed curiosity and intensity. What else could these sturdy wood-like shells transform into?

TACHIO (pronunciation: pistachio) is my ongoing answer to that question.

And as I started creating more elaborate designs, objects, and embroidery, I kept getting another question from people: How often do they break when you’re drilling them?

The answer is very rarely. Like, once-in-a-blue-moon rarely.

But now I had another question: Why? Why don’t they break more often? Why are they so lightweight yet so tough?

The Pistachio Shell: Nature’s Lightweight Armor

It turns out scientists have asked the same question. A pistachio shell is designed to protect its seed (what we call a nut is technically the seed of a drupe aka stone fruit). Instead of relying on mass, the pistachio shell achieves its strength from its dome-like curvature and 3D interlocking cells. While similar in composition to wood, pistachio shells aren’t prone to splitting like traditional tree wood; their dense stone cells lock in with roughly fourteen neighboring cells like a microscopic jigsaw puzzle, distributing stress evenly rather than along a single linear grain line.

Remarkably, when researchers looked at the edges of fractured pistachio shells under a microscope, they found that most cells had “never separated from their neighbors.” In fact, they could see that “splitting the pistachio shell material had required slicing through individual cells."

I find this inspiring on a few levels. And I think about it now as I work—especially when I’m drilling over sixty tiny holes into a single shell that maintains its structural integrity, never cracking or shattering.

Process and Materials: From Raw Shell to Finished Object

Every TACHIO piece undergoes a meticulous, multi-step refining process.

Prep & Surface Tuning: Raw, selected shells are systematically cleaned, dried, drilled, and sanded.

Sealing & Protection: To safeguard against wear and moisture, most pieces are sealed with a nontoxic, plant-based varnish, giving the surface a durable sheen.

Embroidery: For textile pieces, threads are selected based on the foundation material. Priority is given to natural threads, but sometimes polyester/elastic threads are necessary. For the jewelry in the stitched series, a polyester thread is required because the thread ends are heat-sealed to keep the in-shell stitching secured.

Assembly & Hardware: For jewelry, elements are joined with metal hardware, including stainless steel, 316L surgical steel, gold-plated 316L surgical steel, and solid .925 sterling silver.

Explore our catalog, review our product care guide, or reach out with questions.