# What's the mechanism of my candle's wax changing colour when it melts?

**URL:** <https://boards.straightdope.com/t/whats-the-mechanism-of-my-candles-wax-changing-colour-when-it-melts/339308>\
**Category:** Factual Questions\
**Created:** [January 10, 2006, 2:46pm UTC](https://boards.straightdope.com/t/whats-the-mechanism-of-my-candles-wax-changing-colour-when-it-melts/339308 "2006-01-10T14:46:17Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Speaker\_for\_the\_Dead](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@Speaker\_for\_the\_Dead](https://boards.straightdope.com/u/Speaker_for_the_Dead)\
**Post date:** [January 10, 2006, 2:46pm UTC](https://boards.straightdope.com/t/whats-the-mechanism-of-my-candles-wax-changing-colour-when-it-melts/339308/1 "2006-01-10T14:46:17Z")

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This isn’t as simple as the subject may make it seem. The fact is that the change is drastic–from green to red, specifically.

I have a green votive candle that I’ve been burning for the past few days. I stuck a tea-light holder on the bottom of it, so now the remaining wax has pooled therein. Looking down on the melted wax, however, reveals a beautiful wine-red colour (through which I can see the bottom of the holder), rather than a deep green like I would expect. Why?

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**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [January 10, 2006, 3:32pm UTC](https://boards.straightdope.com/t/whats-the-mechanism-of-my-candles-wax-changing-colour-when-it-melts/339308/2 "2006-01-10T15:32:38Z")

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Cameleon candles and [Spa candles](http://www.spacandles.net/index_topic.php?did=52&didpath=/33/52&PHPSESSID=957b294fc304ff6b8bd2d9bc0f43d05b) use RGB LED clusters to effect color changes; not what you describe.  
[Colorsine dyes](http://www.colorsine.com/), produced by United Polymer Technology LLC, are likely what you’re seeing in action.  
[Here’s the patent:](http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/search-bool.html&r=1&f=G&l=50&co1=AND&d=ptxt&s1=colorsine&OS=colorsine&RS=colorsine)

> [@](#):
>
> A positive thermochromic dye, a positive thermochromic wax, and a candle made therefrom (for which we have given our trade name ColorSine A) is one that generates a color on heating or by melting of wax which contains the positive thermochromic dye. This is made by heating together (A) an acid organic dye or an electron donating chromogenic compound selected from the group and list of samples given below under the heading Compound A; B, an electron accepting compound which has carboxyl, hydroxyl, etc. groups attached to the aromatic ring(s)…

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<div class="post-metadata">

**Author:** ![Speaker\_for\_the\_Dead](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@Speaker\_for\_the\_Dead](https://boards.straightdope.com/u/Speaker_for_the_Dead)\
**Post date:** [January 10, 2006, 7:35pm UTC](https://boards.straightdope.com/t/whats-the-mechanism-of-my-candles-wax-changing-colour-when-it-melts/339308/3 "2006-01-10T19:35:13Z")

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Hmm, thank you. Unfortunately, it’s not quite like that. Only the pool of liquid wax displays this property (not heated or dripping wax), and in fact it’s clearly green if I swish it around on the sides of the container a little. I think what’s happening is something simpler, but I just can’t figure out what it would be.