What is Dresser Trap Rock?

Dresser Trap Rock Inc. is one of Wisconsin's oldest industries. It was built in 1914; however Trap Rock has been mined in Dresser, Wisconsin, since 1855. The name comes from the kind of rock being crushed here - Trap Rock - meaning dark, fine-grained igneous rock.
Dresser Trap Rock is a unique, bluish-gray basalt mined and processed in Dresser.
As boulders, it exhibits subtle hues of gray, blues, reds, pinks, and purples.
In crushed aggregate form, its gray color dominates, creating a unique richness unattainable with any other ground cover.

Trap Rock is actually altered basalt, or volcanic (non-porous) rock with irregular seams. It is the hardest known rock in North America. The quality of trap rock deposits varies, in the same manner other mineral deposits vary. The Dresser deposit is the hardest concentration of this bassalt-type rock in America - so hard that boulders from Dresser Trap Rock Inc. were shipped to Maryland for use by NASA in testing drills used on the moon probe.

For further mineralogy information:
Mineralogy of Wisconsin database - created by William S. Cordua:
located on the University of Wisconsin - River Falls website.

Today, Dresser Trap Rock is used extensively in bituminous and concrete applications, erosion and ice control, road construction, landscaping and as ballast for many rail lines throughout the Midwest.

Gray rock is specified by landscape designers to form picture-perfect borders for foundations, driveways, sidewalks, pools, patios, and other applications. It is ideal background color to compliment flowers, shrubs, trees, and all colored structures. What's more, gray rock's innate hardness is ideal for building natural looking, long-lasting structures such as waterfalls and retaining walls.

Beauty and Value that Endures

Count on Dresser Trap Rock to retain its original shape and luxurious color forever. It is inert and unaffected by sun, rain, or temperature. Landscaping with Dresser Trap Rock is a wise investment. You will be rewarded with a lifetime of visual pleasure without maintenance, plus added value to your home, building or complex.