Although there are distinct similarities between flagstones and slate, the two materials are completely different items.

Difference Between Slate and Flagstone

Many people find it difficult to tell the difference between slate and flagstone. In many discussions regarding outdoor home improvement, many people use the words shale, stale, flagstone, bluestone, and landscaping stone interchangeably to mean the same thing. Unfortunately, this confuses some people even further.


Flagstone is a general term used to describe various sedimentary and metamorphic rocks. These rocks are called flagstones because they can be easily split into flat segments to be used to pave patio walkways, build rock walls, and other creative home and garden applications. This means that when a stone is referred to as a flagstone, that is not the specific name of the stone but rather it is a reference to its suitability as a paving stone.


Slate is a type of rock that many people find difficult to differentiate from flagstone. Slate is a popular type of flagstone used in various outdoor applications because it can be easily cut into thin layers, is readily available, and is affordable. In fact, slate is the metamorphosed form of a sedimentary rock known as shale.


Shale is fine-grained sediment that is also an important base component for slate. It is formed when shale sediments form into rocks due to prolonged exposure to pressure below the earth’s crust. Shale is made from organic matter that settles into mud and builds up until pressure turns the organic matter into shale. Because of the large amount of organic matter present in shale, it is an ideal source of natural gas.


This refers to the process of converting shale to slate. Over time, shale below the earth’s crust is forced to move even deeper due to geological forces. As shale is forced to move deeper into the earth’s crust, pressure and heat buildup significantly. Exposure to these extreme conditions for prolonged periods causes the shale to undergo tremendous textural and chemical changes that transform it into slate.

Flagstones are used in Las Vegas as popular and functional decorative pieces in many homes; they are easy to work, readily available, and affordable.