Our quartz stone countertop is make up of 93% nature quartz sand and 7% polymer resins & inorganic pigments. Summerly quartz has natural look vein and pretty color,  and it's environment friendly decorate material.  Our summely quartz not only can be use as kitchen countertop, bathroom vanity, table top, wet bar top,  but also available be used as flooring tiles and wall cladding.

Now there are various brands of quartz, the common thickness is 18 ,20 , 30 mm. Is quartz slab thicker, its quality better?

Well, it's not always right.  Quartz quality is not depend on its thickness but how many quartz sand and resin it contains. Summerly Quartz calculate the most accurate ratio which most close to nature, it means the quartz has high hardness, high scratch resistant.  And the manufacture machine will also affect quartz performance, too.

However,  it doesn't means thicker is worse.  Usually 18 and 20mm is enough for countertop need form most family.  The  30mm thick quartz countertop has higher requirement for the supporting frame. It would be better buying according your actual requirement and specialist's advice.