it could be mold or mildew if it is getting wet. The best way to find out is to pour a small amount of bleach on it and wait to see if it clears up. If it does you  are dealing with biological growth
 

 
On Tue, Aug 25, 2009 at 5:06 PM, rod medel <rodsuperiorstone@yahoo.com> wrote:
Not sure what the stain may be, looks dirty to me.Use a 400g honing powder and you should be good to go,if not then diamonds poultice then finish the area with honing powder

--- On Tue, 8/25/09, Don Kasch <don@floorrestorationspecialists.com> wrote:

From: Don Kasch <don@floorrestorationspecialists.com>
Subject: [sccpartners] black stains in travertine
To: "Restoration and Maintenance" <sccpartners@stoneandtilepros.com>
Date: Tuesday, August 25, 2009, 1:09 PM


Hello and thanks for any help you can give me on this. I sealed a travertine floor with a hydophobic enhancing sealer about a month ago. The lady called about an area of concern, so I went to see the problem. It's an area about 3-4 sq. ft. of blackish stain, looks like its coming from below, like black mold. There is an attached picture of the area, the picture makes the area look lighter than it is but you will get the idea. the sink, referidgerator,and dish washer are no where near this area. whats your best guess, and how would you deal with the stain?
Thanks agian
 

--
Don Kasch
Floor Restoration Specialists
floorrestorationspecialists.com
801.358.0423




--
Frederick M. Hueston PhD
www.stoneforensics.com
www.stoneandtilepros.com
My New Radio Show  www.thestoneandtileshow.com
Become a Stone and Tile Inspector..sign up for our next class in October 2009 (only one class per year is offered) www.thestoneandtileschool.com
888-314-9077
702-314-1017