1.       Resination - Does the stone have a resin finish on it?  Usually you will see drip lines from a polyurethane-like coating on the side. Sometimes resin is applied to cheaper stones to give them better strength.  Generally though, resin is applied to stones either by hand or machine to provide a higher level of sealing.  In either case looking at the materials will give you a good idea if they are coated or not.

2.       Polish - How well has the resin and/or the stone been polished.  The shinier the material, the better the polishing.

3.       Flatness/Tolerance - Generally a thickness deviation of +/- 1/8" is desired. The better processors use better cutting equipment. Running your hand across the surface may sometimes reveal a slight ripple in the surface.  That ripple makes it almost impossible to get a perfectly matched seam.  Better stones are cut using better equipment and are therefore flatter.

4.       Fissures - Look at the surface at an angle with light reflecting on it.  Focus your eyes on the surface.  Do you see any pitting or small fissures? A high-quality stone should have little or no voids or fills.  Feeling the surface will also give you a good indication.  Resinated stones should be completely free of these imperfections. The best materials we have are almost mirror-like in their appearance.  Of course, there are exceptions to this rule depending on the type of material being evaluated.

5.       Color - Only years in the business will give you a good idea of what a stone's reference standard should look like.  Take a color like Black Galaxy.  BG should be very black, not gray, and the best materials should have the largest pieces of Bronzite (the golden flecks of enstatine) in it. They should be a little larger than a pencil eraser. This is a very difficult measure though, as materials like Santa Cecelia can come in a variety of shades.  Color does not necessarily indicate quality. And, color and patterning are subjective.