Mama Red, thanks for the link. There were 2 terms that stood out in the first paragraph: rare; and artificially heat-treated. Since amethyst is not found naturally in green form, then the rarity must be due to this being a relatively new procedure for amethyst, and as soon as others start doing this, it will be less rare.

Stones, especially carnelian, have been sold in heat-treated form for years. I haven't yet seen green amethyst at any of the gems shows I attend, but suspect it will become more available soon.

For those of you who are domestically inclined (and by reading the comments here, I suspect it's a very short list) -- don't bother heating your stones in the microwave. In my ongoing commitment to public service and knowledge -- I've already tried this on a bunch of different stones and it doesn't work. FYI.

If I ever find any housecleaning type stones, you gals will be the first to know.