What Are the Causes of Cracks in Granite Countertops?

Granite countertops are installed in more homes today than ever before. While these stone counters are extremely durable and can last for many years, there are times when the surface can develop cracks. While some of these cracks are natural and part of the stone, others are caused by use or wear and tear on the stone. Learn how to protect your granite from cracks and avoid the causes.

Natural Fissures

Granite is a natural stone product, quarried in huge blocks extracted from beneath the earth's crust. While each type of granite is different in mineral makeup and composition, most granites are igneous rocks made of mica, feldspar and silica. Occasionally, during the formation process of the stone, natural weak spots or fissures occur in the stone. The polishing process of the surface of the stone typically masks or hides these fissures from the eye. Through normal use and wear and tear, a fissure may open wider, becoming a large and obvious crack in the surface of the stone.

Hot Pots

Granite is naturally heat resistant, having been formed through heat thousands of years ago. Constant exposure to heat over an extended period can crack a granite slab, however. The repeated exposure to a hot pot removed from the stove and placed directly on the surface of the granite can gradually weaken the stone, causing a crack to form. If the granite is particularly cold at the time of heat exposure and the difference in temperatures is large, the granite can crack spontaneously as well.

Use Over Time

Extremely old granite countertops that have had their surfaces worn away by constant handling and use can weaken and crack over time. Likewise, heavy objects, such as cast iron pots dropped with enough force on the stone, can cause granite to crack. Granite is at its weakest during transportation. Once installed, the cabinets and plywood underlayment help to protect it. As the stone is carried, moved or stored, it can develop cracks from lying flat without proper support beneath it. For this reason, always carry granite and store it upright before installation.