The quality of granite should be determined and rated by factors such as hardness, consistency of thickness, presence of hairline cracks, proper edge polishing, pitting, graining, and water content.
More Info: Granite pieces vary widely in quality. Some of the variances are determined by the type of granite and where it was quarried, while other differences are accounted for by the means of fabrication, transportation, and overall treatment before it arrives in your home. Understanding these factors can help you to obtain granite that is of the highest quality and value.
Since granite is a naturally occurring mineral, it is difficult to control or manipulate its appearance. This means that a good granite countertop, for example, cannot merely be judged by the uniform color or grain of its pieces, and is also why granite is sold in slabs, rather than in tile form. That is to say, even the highest-quality granite will show wide variation in appearance.
How to rate granite quality, then? Look for the factors not controlled by Mother Nature. Take, for example, the thickness of the slab. Since granite slabs are cut from a larger piece of stone, they should have a uniform thickness. If anyone tries to convince you otherwise, they are lying! A consistent thickness throughout the slab is a hallmark of good craftsmanship.
Look for cracks, even small ones; hairline cracks reduce the durability of your granite slab. Granite should be selected for its smoothness and consistency before it is cut; cracks reflect poor craftsmanship.
Finally, be sure to carefully inspect any granite product for proper edge polishing. Rough edges wear down, and present potential safety hazards. If you are not satisfied with the edge polishing of a piece, don’t buy it, or ask the manufacturer to finish the polishing process properly. Such attention to detail will help you to prevent getting ripped off and ensure that you get a high quality piece of granite for your home!
ScienceDirect – Engineering Geology : Evaluation of the quality of a granite quarry .” ScienceDirect – Home. N.p., n.d. Web. 21 May 2010. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V63-3WCYDK8-1&_user=10&_coverDate=05/31/1999&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1341518129&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid.