Quartz Cracks.
We have been recieving frequent calls about reparing quartz slabs that have cracked along the Inside Corners on L-Shapes onced installed on a Kitchen countertop.  This normally hapens because the fabricator did not gave a minimum-radios & distance when cutting the slab.  For example, if the L-Shape slab piece has less than 10 mm or about less than 3/8 radius as required by the manufacturer then the slab is prone to crack at this location.  This is due to the tension concentrated at a point.

How to repair them?
Normally, a crack like the one on the picture can be filled with a special super thin glue to help prevent the crack opening and growing, however, it can still grow.  Cracks on Engineer Stone are a bit tricky to repair due to their man-made structure.  We haven’t been able to repair them as easy as granite.  Quartz cracks will “walk” over time or the crack will keep growing till the slab is broken.  Granite on the other hand, does not walk or the crack will not grow over time.

Caused of the Problem?
When the slab is cracks at the radius and the radius is less than 3/8 inch it is mostlikely a fabricator error.  No following manufacturer recomendations also voids any claims to their warranties.