"Natural Brass" is a trademark of Vintaj Natural Brass Co. They describe their products as "eco friendly," "hand embellished" and "made in the USA."
We carry Vintaj brass stampings but we do not know what process they use to produce the uniform color of their finishes. Somewhere in their literature I believe it says no chemicals ( or no harsh chemicals) are used. (I couldn't find that claim just now as I looked.)
Is electroplating inherently "environmentally unfriendly?" Potentially that is true. Electroplaters use acid solutions that must be disposed of. State and Federal environmental agencies have regulations about electroplating operations and how spent solutions are disposed of. I do know that Rhode Island plating houses have worked to reduce their impact on the environment.
A lot of business claim to be "green" these days. Some seem to make the claim with very "thin" arguments. Not knowing what process Vintaj uses I can't say if it is any less environmentally harmful than other methods when all the aspects are considered.
Beading in particular and jewelry making in general is not a particularly green or sustainable business although many of us try to be as humane, green and sustainable as possible within this industry. Many of the components we use are ripped from deep inside mother earth often from 3rd world locations, treated with harsh chemicals, cut into small blocks and polished into shapes in poorly ventilated workshops often in 3rd world countries. We use metal that also mined out of the earth and is smelted at high temperatures or extracted with harsh chemicals. We use petroleum based polymer clays to make beads and use lots of energy to cast, fuse, braze and fire our products.
We do all these things because we want to make beautiful pieces of art that people enjoy wearing.
The refiners who produce the silver we sell at Rings & Things claim their silver is "green" in that is all reclaimed or recycled from scrap. That's a good thing. But, somewhere in the supply chain, new silver from current mining is introduced into the marketplace.
I guess what I'm really saying is that a lot of claims about being "green" or "eco friendly" are mostly advertising claims.
I try to counteract some of the problems we create by personally making a difference locally. I insist that Rings & Things recycle and reuse as much as we can. I'm pushing us to use less packaging and less wasteful shipping methods. I've worked for more than 20 years as a volunteer to promote Public Event Recycling and Zero Waste events in the Spokane area. I'm an avid organic gardener, composter and bike rider. When we expanded to our own building we remodeled an older, existing building near the downtown core rather than build a new building in an industrial zone out of town. I tell people we try to "tread lightly on mother earth" but I make no claims about being in a green industry.
I think I just wrote an "op ed" piece.

I hope it answered part of your question.