What is Slate? Slate is a fine-grained, foliated metamorphic rock that is created by the alteration of shale or mudstone by low-grade regional metamorphism. It is popular for a wide variety of uses such as roofing, flooring, and flagging because of its durability and attractive appearance.

Shale has quite a dull look whereas slate shines and looks silky in the sun. Moving on, when treated with water, shale will give you an odour like clay but slate will usually not have any noticeable odour. In some cases however, it may smell like clay but have a very weak odour.

Mineral Properties Slate is a metamorphic rock. Slate ranks at 5.5 on the Mohs scale. It is hard enough to be able to scratch glass and steel.

Slate is a a type of rock often referred to as flagstone. In reality slate is a low-grade metamorphic rock. Slate is popularly used for flagstone because it is very easily split into thin layers and is extremely common and reasonably priced. Slate is actually the metamorphosed form of the sedimentary rock shale.

The gold crystals are likely to be pyrites, a type of metal inclusion that is present in all natural slates, but not always visible. Visible, stable Pyrite inclusions in a T1 rated Scottish Roofing Slate. Some pyrites may cause staining or even holing.

Does slate absorb water? Slate has a very low water absorption index making it almost completely waterproof, one of the main reasons why slate is a preferred material for roof tiles, cladding and tiles in wet-rooms as well as for countertops in kitchens.

metamorphic rock

pumice

Just like a sponge, porous rocks have the ability to absorb water and other liquids. These rocks, including pumice and sandstone, increase in weight and size as they take in water. Some of the rocks will absorb a large amount of water, while others may absorb very little.

Flagstone

One of the many uses of river rock is to encourage drainage. Because the round stones do not fit as tightly together as other materials, water can flow through cracks between the stones. This type of drain rock is also a great tool for xeriscaping, which is a style of gardening that requires very little irrigation.

Marble is prone to degradation and etching from acids and common household cleaners, and it’s incredibly porous and will absorb water and moisture more readily than other stones.

As natural stones, marble and granite countertops have varying degrees of porosity, which means that yes…they will indeed absorb water. The amount of absorbency varies depending on the exact type of stone. For example, denser igneous stones like granite absorb less liquid than their metamorphic counterpart, marble.

Wet stone is always darker in color, so the white marble tiles become gray and stay gray since they are saturated with water. The sealer prevents absorption into the stone, but it can also prevent water from evaporating out of the stone especially when the tile is on a floor or wall.