Rocks With Soul: Hedberg Landscape & Masonry Supplies

Today’s blog is provided by Steve Hedberg, Founder and President of Hedberg Landscape and Masonry Supplies.

Over the last 25 years of being in the business of providing landscape supplies and later adding stone and brick for masonry, I have developed a couple of passions that relate to our business. I have decided to share my passion for rocks through a basic introduction to rock geology.

The Earth is active and its continuous change creates three categories of stone, each of which is commonly used in landscaping and masonry. These three categories are igneous, sedimentary, and metamorphic rocks.

Igneous

Igneous rocks are composed of molten minerals and gases found as deep as 50 miles inside the earth’s crust. Heat and pressure within the earth cause these minerals and gases to form a volatile liquid rock called magma. This magma either rises to the earth’s surface during volcanic activity or stops below the surface and slowly cools there.

Extrusive igneous rocks occur when the magma cools after reaching the earth’s surface. The lava cools at a faster rate, which causes small or no crystals in rocks like basalt. Intrusive igneous rocks are created when the lava cools at a slower rate under the earth’s surface, causing very large crystals in rocks like granite.

Sedimentary

Sedimentary rocks are made from debris of stone and organic matter that has been broken down by the action of wind, rain, rivers, glaciers or gravity. These same forces move and resettle the debris, during which process it becomes solidified or consolidated in layers that are easy to split during quarrying. Sedimentary rocks can be classified as both clastic and non-clastic rocks.

Sedimentary Sandstone

Clastic sedimentary rocks are made from weathered rock debris that has been physically transported and deposited. During the transportation process, the particles that make up these rocks often become rounded due to abrasion. A common example of clastic sedimentary rock is Sandstone. Locally used examples include New York Bluestone, Highland Brown or Sandy Creek. Non-clastic sedimentary rocks are created from chemical precipitation or more commonly from organic matter. Two common examples of a non-clastic sedimentary rock created by organic matter are limestone, which is a mixture of shells, coral, and other marine skeletons, and coal, which is created by the lithification of remains of plants.

Metamorphic Rock

The third type of rock, metamorphic rock, is a rock that is transformed from pre-existing rocks into another kind of rock due to heat and pressure. Examples of metamorphic rock include:

• Marble, which is a metamorphed limestone
• Quartzite, which is metamorphed sandstone
• Slate, which is metamorphed shale
• Gneiss, which is metamorphed granite

The category of a stone determines how it can be quarried – whether it can be split into layers, gathered or needs to be sawn into slabs. In my next blog, I will discuss the three main quarrying techniques for stone used in residential construction, which have a direct correlation to the three categories of stone.