What the ...?

[TRex]

Now that the puzzle is closed, I must question the commonness of verdigris. I don't know that I've ever seen it and I sure as heck did not know what it meant. (My wife kept trying different letter combinations and hit on it and told me.)

In comparing verdigris to recently made uncommon words worshiped, subaltern, and rime, the Ngram Viewer shows verdigris has been less common than all of them for at least 150 years. And to use such an obscure word as the seed!

Please reclassify this, Alan!

[Greynomad]

It was a challenging word, but one which I knew as soon as I found it, and knew what it was.

I would be disappointed if it were reclassified, as it is the challenging common classification words that make the game interesting.

[mkenuk]

Most definitely common as far as I am concerned - I learned it in first-year Chemistry sixty years ago.

We used to put old copper pennies which were showing signs of verdigris in acid and watch them turn out as bright and shiny as new.
I'm told the same thing happens if you put them in Coca-cola!!

Americans must have seen examples of verdigris -

She wasn't that colour when the French presented her to them!!

[anona]

I saw it without much trouble, and I know what it is - not through Chemistry lessons, but just life (architecture, pennies, as mkenuk says). I'm surprised Ngram has it so infrequently: a google search on "verdigris garden" for example brings up loads of references, including ones on Amazon and ebay sites. But do Americans just call it by the generic term "patina"?

[yelnats]

Verdigris was the first word I got; it just jumped out, but after the previous posts I realise I was wrong in its meaning, confusing it with ambergris.

[Ozzyjack]

Was this after too much Pinot Gris? 

I had trouble finding it despite the fact that it was quite familiar once found.

[rogue_mother]

I did not have the least bit of trouble with verdigris. But then, I also did not have trouble with rime or subaltern; I knew the meaning of these words before ever playing Chihuahua. Ignorance of verdigris cannot be laid on one's being American.

[TRex]

But do Americans just call it by the generic term "patina"?

That is all I've ever heard.

The website https://www.worldcoppersmith.com/copper-patina-guide/ never uses the word verdigris.

[birdy]

Maybe because I'm in NYC and can see the Lady in the Harbor?  I've seen many articles over the years and they all mention the color of the statue being caused by verdigris.

But I think I knew it before I came to NY, because of copper pennies.

And I've seen it more recently in craft/DIY magazines in relation to working with copper.

I wonder what Ngram uses as a source for its count.

[anonsi]

It's also used in a line in the hit musical, Wicked.
https://www.youtube.com/watch?v=uZyQwjVRT5c

[ensiform]

For what it's worth I think it's a common word.