Thunder Bay Amethyst Revisited

en.wikipedia.org/wiki/Vermarine

Read the first paragraph in the link provided. Note the reference to its availability from Thunder Bay.

The third paragraph is interesting due to the fact that you mention seeing oranges and yellows:

"It is a rare stone in nature; artificially produced vermarine is heat treated amethyst.[4] Most amethyst will turn yellow or orange when heated producing citrine. But some amethyst will turn green when treated. Currently, almost all vermarine on the market results from a combination of heat treatment and ionizing radiation.[6]"

Making me wonder if you purchased the rough from one of the Thunder Bay merchants that they may have experimented with some heat treating, OR, you got lucky and found some with natural vermarine mixed in with citrine and amethyst. The clear can be found with most amethyst and is just quartz.

Last but not least, my personal collection of specimens from Thunder Bay actually has some very similar colors to what yours has although I am not about to tear out a crystal to show the two in one.
maybe a better photo to illustrate the two colors in one matrix:


Another pic showing green and purple together from Thunder Bay:

While some of my specimens have yellow and orange crystals which look to me like citrine, they do not mix much with the green and purple in the same crystal.


The pic below shows some of the same lot with only amethyst crystals:


The back side of one of the mixed green and purple. Seems it even is apparent on the back:


My guess.

I'm going to guess that amethyst produced by manganese will fade to citrine and amethyst produced by iron fades to green. It would be interesting to know the source of color at thundebay.

I could have it backwards!

I'm pretty sure that's the stuff I have. The green is not technically amethyst though and it is not a result of fading or changes in the color of purple amethyst.
The following text taken from that post distinctly separates the what it calls green quartz from the other varieties including amethyst:

The TBAMP system contains a number of color varieties of quartz including greenish, amethyst, colorless, and smoky. Spectroscopic, irradiation and controlled heating studies show that changes in salinity and temperature of the hydrothermal system that produced the TBAMP deposit are reflected in the changing coloration of the quartz. The greenish quartz, especially the greenish gray variety, has increased turbidity and fluid inclusions in comparison with the adjacent amethyst.

The following excerpt is from the wiki on amethyst which also points out the fact that amythyst is never green:

Amethyst occurs in primary hues from a light pinkish violet to a deep purple. Amethyst may exhibit one or both secondary hues, red and blue. The best varieties of amethyst can be found in Siberia, Sri Lanka, Brazil and the far East. The ideal grade is called "Deep Siberian" and has a primary purple hue of around 75–80%, with 15–20% blue and (depending on the light source) red secondary hues.[4] Green quartz is sometimes incorrectly called green amethyst, which is a misnomer and not an appropriate name for the material, the proper terminology being prasiolite. Other names for green quartz are vermarine or lime citrine.

The two can however be found side by side and when that occurs it is caused by hydrothermal sources.

Praisolite is one of the names given to green color quartz. I like your crystals, nice transition of praisolite to amethyst color zoning. Its it all pretty included or is there any facet grade stuff?

To me Amethyst is Purple or lavender. So this is Amethyst with other stuff mixed in. Lots of great info here, which I appreciate.