# Why does "Gold Leaf" Tarnish?

**URL:** <https://boards.straightdope.com/t/why-does-gold-leaf-tarnish/407885>\
**Category:** Factual Questions\
**Created:** [June 13, 2007, 6:40pm UTC](https://boards.straightdope.com/t/why-does-gold-leaf-tarnish/407885 "2007-06-13T18:40:07Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\
**Post date:** [June 13, 2007, 6:40pm UTC](https://boards.straightdope.com/t/why-does-gold-leaf-tarnish/407885/1 "2007-06-13T18:40:07Z")

</div>

My town libabry redecorated the interior about 5 years ago. Included in the job was re-guilding some decorative plaster strips in the ceiling-I belive it was quite expensive.  
i happened to look up at one strip-and it had turned green! Now, i thought that gold did not oxidize or tarnish-so was the re-guilding done with some metal which was NOT gold?  
Shouldn’t gold lef be good forever?

---

<div class="post-metadata">

**Author:** ![slaphead](https://avatars.discourse-cdn.com/v4/letter/s/e9bcb4/32.png) [@slaphead](https://boards.straightdope.com/u/slaphead)\
**Post date:** [June 13, 2007, 7:39pm UTC](https://boards.straightdope.com/t/why-does-gold-leaf-tarnish/407885/2 "2007-06-13T19:39:50Z")

</div>

[QUOTE=ralph124c]  
My town libabry redecorated the interior about 5 years ago. Included in the job was re-guilding some decorative plaster strips in the ceiling-I belive it was quite expensive.  
i happened to look up at one strip-and it had turned green! Now, i thought that gold did not oxidize or tarnish-so was the re-guilding done with some metal which was NOT gold?  
Shouldn’t gold lef be good forever?  
[/QUOTE]

Take a look at this [gilding glossary](http://antiquerestorers.com/Articles/GOLD/GLOSSARY2.html).  
Key points:

> [@](#):
>
> Gilding: To overlay with or **as if with** a thin coating of gold

> [@](#):
>
> Gold Leaf: Gold beaten to the point of being transparent  
> …  
> The advantages of a gold leaf finish as opposed to other gold colored finished are: Its reflective quality (The beaten leaf has more reflective quality than anything produced with pigment), its durability (properly gild surfaces can last for centuries) and its stability ( **it does not tarnish** )

> [@](#):
>
> Bronze Powder: Particles of bronze used as a pigment and mixed with a medium to produce a gold-colored finish. **These finishes tarnish** due to the copper content of bronze powders.

[my emphasis]  
To be honest, I’d be a bit surprised if a town library could afford to have its ceiling decorated with gold leaf. The material seems to come in at about a dollar per leaf (5.5"x5.5"), so might not be such a huge deal unless there’s lots of area to cover, but I would imagine the labour cost might be fairly eyewatering - it’s not the sort of thing your average painter would be able to do.

---

<div class="post-metadata">

**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\
**Post date:** [June 13, 2007, 7:41pm UTC](https://boards.straightdope.com/t/why-does-gold-leaf-tarnish/407885/3 "2007-06-13T19:41:35Z")

</div>

Since it turned green, I would suspect that it’s copper and not gold.