Dear Joe:
It does sound like it stabilized.
As for the repair, without actually seeing it, I can hardly tell. But the first thing that comes to my mind is this: is the crack wide enough to let anything in?
I mean, both epoxy and grout have some “body” and need room to go in. If your crack is not even all the way through, I highly doubt that you have any significant gap that should be at least 1 mm.
The ideal would be to mix flowing clear polyester glue (that is what they improperly call epoxy, most of the time) with sand less grout (approx. 70 glue to 30 grout), and then play with the white to match the color. Add the hardener, fill the crack, let the filler cure, grind it flush and finish to match the rest of the slab. But then again: you must have enough width in the crack to possibly do that. If you don't, one way of doing that is to widen it with a special blade; but only a precious few stone restoration contractors know about this technique.
May I ask you now to please read and e-sign our Statement of Purpose at:
http://www.marblecleaning.org/purpose.htm?
Ciao and good luck,
Article ID: 1106
Created On: Sun, Jan 27, 2008 at 2:09 PM
Last Updated On: Sun, Jan 27, 2008 at 12:00 AM
Authored by: Maurizio Bertoli [mail@mbstone.com]
Online URL: https://marblecleaning.org/knowledgebase/article.php?id=1106