Aggregates Manager

Bill Langer is a consulting research geologist who spent 41 years with the U.S. Geological Survey before starting his own business. He can be reached at Bill_Langer@hotmail.com CARVED IN STONE 32 AGGREGATES MANAGER / May 2018 A bout eight years ago, I wrote a two-year series of articles with the overall theme "From A to Z." I used the alphabet to describe terms related to aggregates and industrial minerals. The first article, per- haps no surprise, was "A is for Aggregate." The fourth article was "D is for Diamonds." The article actually was about the dimension stone industry and how it has been impacted by industrial diamonds. I feel bad about slighting dimension stone in the title of the article, so today, I revisit the subject and give dimension stone top billing. Dimension stone can be grouped into three overlapping classes based on whether the stone is naturally occurring and used without further treat- ment, or if it is cut, trimmed, sawed, or polished. Naturally occurring dimension stone includes blocks or slabs that have naturally weathered out of local bedrock, as well as large cobbles or boul- ders. These are referred to as fieldstone, which are gathered from the land surface and used to make stone walls, build fireplaces, and so forth. Paving blocks are small brick-shaped blocks of granite used to pave ar- eas of heavy traffic and in reclaiming streets in historic areas. Flagstones consist of thin slabs of stone used for paving. Flagstone may be used in irregular shapes or may be cut or split into rectangular shapes. Fine-grained sandstone and slate are the most common type of flagstone. Ashlar are small blocks of stone that are split into rectangular shapes with a power wedge called a guillotine. Ashlar may be of modular or ran- dom sizes, resulting in building facades, hearthstones, or fireplaces with either regular or unequally spaced joints and a seemingly endless variety of designs. Ashlar is one of the most common types of cut and trimmed dimension stones. Roofing slate is used in new construction and in the restoration of older buildings. Mill stock slate is smooth finished slabs of slate that are used for billiard tables, blackboards, countertops, and other applications. Sawed and polished blocks of stone include grave markers, mausoleums, and elaborate structures, such as the Washington Monument. Let's not forget about carving stone — the marble, granite, tuff, serpentinite, travertine, and alabaster; rocks commonly used by artisans to create statuary ranging in size from desktop pieces of art to grand monuments such as the Lincoln Memorial. A relatively new product is a lightweight, very thin reinforced stone veneer panel laminated to a backing material. The new products have led to new applications for design, including outfitting of luxury yachts, and has brought attention to translucen- cy, a previously unrecognized property of stone. Automated cutting and polishing machines, and the use of industrial diamonds (as I pointed out years ago), have reduced the price to where stone can be used in many residential applications. Slabs of stone can be cut into square or rectangular shapes that can be used for tile, counter tops, and building facades that we see almost every day as we visit banks, depart- ment stores, and other public buildings. I absolutely love looking at those stone slabs, and don't even mind waiting for assis- tance at a store if I can gaze into polished rock countertops or study the vein patterns in the floor tiles while lingering around. I also find the names of polished rock fascinating — monikers like Ametista, Cosmos, Marrakech, Rapakivi, Tempest, and Zeus. Ametista to Zeus. There you go. Dimension stone from A to Z. AM In a series of articles 'From A to Z,' diamond previously got top billing. Now, it's dimension stone's turn to shine. D is for Dimension Stone Ashlar, one of the most common types of cut and trimmed dimension stone, is often used for building facades, hearthstones, or fireplaces.

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