Bluestone is fast increasing in popularity, however there is a lot of confusion on what is bluestone. I live in Australia but got an email question from a person residing in
the U.S.A. who had looked at our website. She said she was completely confused on what bluestone really was.
To begin with, bluestone is not a geological term and does not fall within any distinct category such as igneous, sedimentary or metamorphic. Bluestone, in fact, represents in excess of 20 separate rock varieties.
In the U.S. it is usually a kind of sandstone. It is deep blue in colour, but in other areas of the U.S ,it is a variety of limestone that was formed in deep water and had less subjection to light. Because of this the rock eventually fades from a deep blue to a light grey after it has been exposed to the sun. This also applies to bluestone in Canada and Belgium.
In Australia there are two varieties of bluestone, one normally known as Victorian Bluestone which is a kind of basalt. Basalt is an igneous rock made up primarily of feldspar and is usually grey to black and fine-grained owing to rapid cooling of lava at the surface of a planet. In South Australia, it is known as a type of slate. Slate is a metamorphic rock which is mostly made up of quartz and is typically pale grey or beige in color. It should be noted that it is a great deal less hard-wearing than the Victorian Bluestone.
Chinese Bluestone is generally a grey limestone. Limestone is a sedimentary rock that is mainly made up of minerals calcite and aragonite, which are dissimilar crystal forms of calcium carbonate
Bluestone as found in the U.K., the most famous being the stones of Stonehenge, is more specially known as Preseli Spotted Dolerite, found in the Preseli Hills of Wales. Dolerite is of a similar composition to basalt.
Bluestone found in New Zealand, also known as Timaru bluestone is similar to Victorian Bluestone and is also know as a grey basalt. New Zealand bluestone is primarily quarried in the vicinity of Timara in the south island (hence it’s name) also near Kokonda, central Otago.
What one should do if looking for bluestone particularly if you are looking for bluestone tiles or bluestone pavers, is to ascertain precisely what sort of stone they are. For example, if you are looking for bluestone tiles made from basalt you would hardly want to be presented with bluestone tiles formed from sandstone. sandstone is much softer and not quite as hard wearing. Take your local suppliers guidance on what sort of stone tile is the best for the situation in which you desire to make use of them. It is also extremely important to know just how the kind of bluestone selected changes in colour after extended exposure to light.
You can find out more about bluestone click on “Bluestone“.