Cobblestone Definition Explored
Posted by Robert Kean on Thu, Oct 13, 2011 @ 10:14 AM
What is the Definition of Cobblestone?
If a group of design professionals and stone installers were asked "What is cobblestone?" the answers would be varied. Cobblestone means different things to different people. Old stone streets might be the only common agreement. Common perception is of some type of stone paver, and not man-made.
Wikipedia has the following definition of cobblestone:
Cobblestones are stones that were frequently used in the pavement of early streets. "Cobblestone" is derived from the very old English word "cob", which had a wide range of meanings, one of which was "rounded lump" with overtones of large size. "Cobble", which appeared in the 15th century, simply added the diminutive suffix "le" to "cob", and meant a small stone rounded by the flow of water; essentially, a large pebble. It was these smooth "cobbles", gathered from stream beds, that paved the first "cobblestone" streets.
Note that cobble is a generic geological term for any stone having dimensions between 2.5–10 inches. A cobbled area is known as a "causey", "cassay" or "cassie" in Scots (probably from causeway). Wikipedia Cobblestone
The definition includes an expectation of size - although highly varied. The historic use of cobblestone goes back to Roman times and earlier. The Romans were certainly some of the earliest pioneers of road design and engineering. In most cases the determining factor in deciding which stone was used was the proximity of the stone - not suitability. Moving stone in ancient times was difficult. The thinking of the time was that almost anything was better than carts sinking up to their axles in mud, and so stone near the road was chosen.
The Romans are the only ancient civilization (that we are aware of) that valued a stone paving material enough to transport it over great distances. The mountains of Northern Italy near Trento have vast deposits of porphyry, and it was used beyond the region from which it was extracted. Quarries are are active in the region today.
The Romans moved stone from greater distances in their empire than Northern Italy. After Egypt was conquered, deposits of a purple porphyry were discovered. The Romans valued the stone so highly that this porphyry was quarried, transported by cart to Egypt's Mediterranean coast, and moved by barge to Italy. Purple porphyry was used for temples and statuary. See the story of the discovery of purple porphyry and the porphyry road .
Differences
The word cobblestone invokes the idea of rounded river stone in many people's minds because of the historic definition. In the Wikipedia definition, the root of the word in old English is "rounded lump" See picture below. However, the Wikipedia definition also acknowledges cobblestone as a generic term for many stones.
rounded cobblestone - picture by Paul Maxim Photography
The use of the word cobblestone has evolved over time. It now refers generically to stone paving or stone streets.
In the modern frame of reference for most people, stone's use as a paving surface is in the past. Most think of pavement as concrete or asphalt. This is largely due to post-war growth that forced the adoption of cheap and quick paving methods. The fact that these solutions are not durable and cost more in the long term were not part of the equation.
Cobblestone for Modern Use
One of the preconceptions about cobblestone is that it is hard to walk on. Rounded cobbles certainly are difficult to walk on, but not all cobblestone is rounded. Not all cobblestone is the same.
There is cobblestone which is flat; has texture; and meets ADA standards for both smoothness and slip resistance.
Milestone Imports Copper Mountain Porphyry at Stanford University, Palo Alto, CA
Porphyry Cobblestone
Porphyry cobbles are naturally textured, yet flat. In addition to being smooth, one of the reasons the Romans valued porphyry was that it forms mainly in stratified layers, making it easy to extract. Closely related to granite in its mineral composition, it naturally cleaves into layers during formation (the divisions are usually vertical). The stone is still forming when the cleaving occurs, causing the stone to cool more rapidly - and smaller crystals to form around larger crystals. This gives porphyry its unique appearance. The stratified layers make the stone easier to extract - despite the fact that it is as hard, or harder, than granite.
The Romans valued porphyry for its beauty, durability, and ease of extraction. The same can be said of modern Europe and South America, where porphyry is used as paving today. Rounded cobbles are no longer used and only retained in historic preservation.
The good news for North America is that Milestone Imports has developed sources of porphyry closer to home: in Mexico and Patagonia. Porphyry is growing in use as a hardscape material here in the U.S. and Canada. Increasingly architects, landscape architects, and designers are seeking design elements that make their projects stand out from the rest of landscape and cityscape. Here in the U.S. porphyry has been introduced to city streets, parks, plazas, memorials, monuments, religious institutions, and residential driveways and patios. It is chosen for its beauty and permanence - lending both to the design.
Porphyry is a time-tested cobblestone paving material that meets the needs of modern times.
Milestone Imports Copper Mountain poprhyry installed as a street
