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Worried about trees? You can write on paper made of rock

A newer environmental technology makes paper mostly out of reused rubble from quarries and construction. Be careful about recycling it, though.

Karst Stone Paper

Karst Stone Paper.

Stephen Shankland/CNET

No doubt you know paper comes from smushed-up trees. But Karst Stone Paper and a host of other brands hope we'll all adopt an alternative made from -- you guessed it -- smushed-up rocks.

The paper is waterproof, durable and more environmentally friendly, Karst and other stone paper companies argue. No trees are needed, of course, but also no bleaches and comparatively little water. It's even gained enough attention to irritate traditional papermakers.

Rock dust may not sound like an ideal ingredient for paper, but it works. Karst's paper is made of about 80% calcium carbonate, the main ingredient in limestone and marble. A Taiwanese supplier, Taiwan Lung Meng Advanced Composite Materials, pulverizes the rock left from construction and quarries, fuses it with plastic that holds it together, then compresses it with massive rollers until it's paper-thin.

The environmental benefits of stone paper aren't entirely clear, especially given some serious limits on recycling. But it's one example of some of the fundamental rethinking happening today as researchers and businesses look for eco-friendly ways to get things done. Electric vehicles are making inroads on internal combustion engines, meat is being made from plants, quantum computers embrace the very physics that stymies ordinary machines, and 3D printers form products by putting material where it's supposed to go instead of grinding away the excess.

Australia-based Karst Stone Paper, which sells notebooks for $20 and hopes to expand to printer paper, is one of many brands you'll see. Others include ImStone, A Good Company, Rockstock and FiberStone, but you can find others with a search for "stone paper." Some companies use stone paper -- also called mineral paper -- for things like labels, bags, packaging and even food trays.

What stone paper is like

I tried out a compact Karst Stone Paper notebook -- look out, Moleskine -- and found it fine for taking notes in pen, though unfortunately it didn't improve my handwriting. My son's tests confirmed it worked with pencils and crayons, too.

Karst Stone Paper

Test-driving Karst Stone Paper.

Stephen Shankland/CNET

The paper itself feels a bit smoother than conventional paper since it's made of tiny particles and not a rougher matting of plant fibers. But it's also tackier, like latex, and I experienced more drag as pen tips slid over the surface.

The presence of the plastic is also noticeable when you tear the paper: It stretches first.

But because the paper is waterproof, the wet ink of fountain pens and felt-tip pens is a problem. That might be a bummer for an artist like Mattias Adolfsson, who likes old-school fountain pens, but most people won't have a problem.

It can be used in inkjet printers, but laser printers are off-limits because of their heat and the plastic in the stone paper.

How about the environment?

Stone paper obviously doesn't use trees, a dwindling resource as forests disappear at an annual rate of about 13,000 square miles per year, according to the United Nations. Much paper comes from trees that the forestry industry plants specifically for later harvesting.

Calcium carbonate, in contrast, is a common mineral that in stone paper's case is collected from mining and construction waste -- at least at the current rate of stone paper manufacturing. You might be familiar with one common calcium carbonate incarnation, chalk.

Lung Meng and several stone paper sellers tout the paper's ecological advantages. A big one is lower water use. Stone paper production requires 27 gallons of water per metric ton, compared with 15,500 gallons for dead-tree paper, Karst says.

But one organization representing papermakers isn't happy with Karst's claims. "It has come to our attention that spreading misconception about killing trees to promote your product is impacting our industry negatively," wrote Kellie Northwood, CEO of Two Sides Australia and New Zealand, a group that represents forestry, paper and publishing companies, in an October letter to Karst. Two Sides didn't immediately respond to a request for comment.

Karst CEO Jon Tse is unruffled. "First they ignore you, then they laugh at you, then they fight you, then you win," he said, repeating a quote you'll hear often among tech upstarts.

A Karst Stone Paper notebook

This Karst Stone Paper notebook looks like an ordinary compact notebook, but it's made of rock dust fused with plastic.

Stephen Shankland/CNET

But how about recycling stone paper?

When you want to toss your stone paper notebook, things get more complicated. Stone paper can be recycled, and indeed Karst Stone Paper and Lung Meng do so. Karst recommends tossing it into the bin that handles No. 2 plastic -- high-density polyethylene, or HDPE, the type stone paper uses.

Lung Meng also has secured silver-level certification from Cradle to Cradle Certified, an organization that evaluates companies' safety and sustainability.

But you'd better ask your local agency before tossing your leftover stone paper into the recycle bin. Stone paper isn't common, and sorters are likely to see it as paper. My recycler didn't know how to handle it at this stage. "It's hard to evaluate something we don't know about," said Julia Au, a spokeswoman for RethinkWaste, which handles recycling for several San Francisco Bay Area cities. One New Zealand recycler advises you just put stone paper in the trash can.

And a company that handles hundreds of tons of recycled material each day said it wouldn't put stone paper through either paper or plastic recycling processes. "This would be considered contamination for both of those markets," a representative said.

Stone paper degrades in six to 12 months in sunlight, Karst and Lung Meng say. But don't drop it in your compost bin, because unlike paper, it won't biodegrade.

Still, there are those trees to think of. Forest growth is a good way to capture the carbon dioxide that's triggering global warming. And Karst Stone Paper encourages people to mail back used paper for its twice-yearly shipments to Lung Meng. Unlike tree-based paper, stone paper can be recycled over and over. Maybe someday recycling will be more widespread.

"We would love to build facilities around the world that could recycle stone paper time and time again," Tse said.

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