It sounds like a joke: Adding microscopic particles of pulverized rock into a fabric to enhance its heat-dissipating capabilities. But it's not. It's the new Armachillo product line from Duluth Trading Company, a Wisconsin-based apparel company that specializes in outdoor work wear.
Even the company's press release sounds tongue-in-cheek. "Armachillo gear is featherweight, sweat-sapping, tough-as-blazes, UPF sun protective and will save your skin when summer seethes," it reads. The web site description further elaborates: "Put it on and chill out—even when the job site's hotter than the hinges of hell."
Both the press release and web site are light on details, however, as to how exactly "microscopic jade embedded in the fabric dissipates heat and cools skin to actually lower body temperature."
It does seem possible, though, given that jade (like essentially all rocks) has very low thermal conductivity. That is, it absorbs heat very slowly and would take a long time to warm up even in hot conditions, which means it could remain cool relative to your body for an extended period of time.
Alternatively, as X-breath fabrics explains, it's possible that the physical structure of the jade particles is what provides the enhanced cooling effect. Or it could all just be the latest attempt at an innovative marketing strategy. (As I like to say, most "high-tech" outdoor materials are 90 percent marketing, 10 percent science.) Hard to say, really.
One of the most inexpensive ways you could test out its capabilities is to purchase a short sleeve Armachillo Tee ($34.50). Other products include cargo pants ($69.50, pictured), a wide brim hat ($29.50), and a few women-specific products. All Armachillo items are made from lightweight nylon, feature an odor-fighting anti-microbial finish, and are available in tall sizes for an additional $5.
“Equipped” is an AMC Outdoors blog, written by Matt Heid.