Natural Stone Products


8200 Seven Locks Rd.
Bethesda, MD 20817

Quarry and Yard

8200 Seven Locks Rd.
Bethesda, MD 20817
Fax: 301-365-5524


Carderock® Quarries, trading as Tri-State Stone® & Building Supply, Inc. and Ben Porto & Son, Ltd., has been family owned and operated since its inception in 1926. The stone is a mica-schist quartzite. The vibrant blues, browns, greys, and greens create an aesthetically pleasing mixture of colors for various types of stone projects. The quartzite gives the stone durability while the mica-schist establishes its unique horizontal and vertical cleavage, making the stone easy to work. The colors, durability, and ease of use have made Carderock® Stone a favorite of stone masons, architects, designers, and homeowners for generations.

Entire homes or house fronts, fireplaces or walls, residential or commercial landscape applications, new construction or remodeling - all benefit from the lasting beauty and timeless appeal of Carderock®Stone.

Tri-State Stone® & Building Supply, Inc. is committed to providing you with high quality natural stone on a consistent basis. In addition to Carderock® Stone, we are dealers of a wide range of natural stone products and operate twelve months per year to give you an uninterrupted supply of stone.


{{}} {{this.hide}} Veneer Stone

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Veneer Stone - Carderock®

For use in walls with setting beds of 4" to 6", such as house fronts, fireplaces, chimneys, or any job requiring stone facing. The stone is somewhat irregular in shape, many with reasonably square edges for corners, 6" to 12" in height, and lengths up to 60". Coverage of 30 to 35 square feet per ton can be expected for rubble style applications.

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Garden Wall Stone - Carderock®

Irregular in shape and somewhat flat, this grade of stone is ideal for dry of semi-dry stack retaining walls up to 24" in height, such as those defining a raised garden bed. With one reasonably good face, 8" to 12" deep, 3" to 6" in height, up to 18" in length, coverage of 18 to 20 square feet per ton can be expected.

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Drywall Stone - Carderock®

Somewhat flat and irregular in shape, many stones will have one good face. Suitable for dry and semi-dry retaining walls, the stone averages 8" to 14" in depth, 4" to 10" in thickness, and up to 24" in length. Approximate coverage is 12 to 15 square feet per ton.

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Flagstone - Carderock®

Suitable for use as stepping stones or coping. Broad and relatively flat, from 2" to 4" in thickness and 1.5 to 5 square feet in area. Coverage of 45 to 50 square feet per ton.

{{}} {{this.hide}} Landscape Boulders

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Landscape Boulders - Carderock®

Varying shape and dimension, from 300 pounds to 5000 pounds in weight.

{{}} {{this.hide}} Tumbled Stone

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Tumbled Stone - Carderock®

All the beauty and distintive color range of Carderock® Stone tumbled smooth as if it had been in a riverbed for eons. Perfect for use as a ground cover, in water features and dry stream bed applications.

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Last Update: 2019-09-24