A Guide to Stone Quality

Natural stone is often selected for its personality and character; the flowering found in Granite, the veins running through Marble or the cats paws scattered through Bluestone. While some ‘imperfections’ are sought after there are some traits which are considered poor qualities when stone is being used in paving applications.

It’s important to keep in mind that, while the following traits can be considered indications of a lesser quality product, some of these imperfections are open to personal interpretation. As an example, rusting can occur in some stones which may be the desired effect for certain projects.

If you’re unsure whether an imperfection is sign of character or a poor stone quality make sure you speak with your supplier or installer.

 

Discolouration
Stone is a natural product and, as with all natural products, a certain amount of colour variation is to be expected. The type of stone (granite, bluestone, travertine, etc) will determine which variations you can anticipate but, regardless of type, the general hue should not vary significantly from paver to paver.

Travertine is an example of a product that’s known for its variation in colour and is actually sought after.

It’s important to understand the extent of the colour variation you might expect when looking for a natural stone product so make sure you ask your supplier.

Rusting
Some natural stones contain inclusions of Iron Pyrites which, when exposed to water or oxygen, can corrode to form hydrated iron (III) oxide, or rust, and may leave behind a brown/red mark on the stone surface.

It’s impossible to know whether a block will include Iron Pyrites before the manufacture process but there are some stones which are more prone to this than others. When speaking with your supplier they should let you know if the stone has a history of these inclusions and what to expect.

Sealing your stone after installation can help prevent rusting as it minimises the chance of water penetrating the stone. If you’ve purchased a product which appears to be rusting don’t despair, in most cases this is something that can be cleaned from the surface.

 

Stone Quality - Variation and Chipping

Discolouration

Bluestone at a factory with massive colour variations and chipped edges. This product was being prepared to send to another supplier in Melbourne but is something Granite Works would reject.

 

Joints and Fillers
Some stones contain natural fissures – which is another way of saying cracks which haven’t separated. In almost all cases these fissures aren’t problem, as long as the stone is installed properly, but they can be visually unappealing depending on your personal preferences.

If the fissures are large enough that your fingernail catches in them, or you notice them changing over time, then it could be a problem with the stone or with the installation. In the majority of cases where fissures change over time there’s a problem with installation such as inadequate drainage or poor adhesive application.

If your stone has noticeable glued cracks, joints or filled and discoloured areas it may be the sign of a sub-standard quality control process. At Granite Works we take pride in our quality control as we invest large amounts of time and resources into ensuring we supply only high quality product.

Identified Problems
If you’ve purchased natural stone and are concerned that there could be a problem, or you think you may have a substandard product, it’s important to let your supplier know before installing.

If you have any questions or enquiries about selecting the right stone for your project the team at Granite Works would love to hear from you on 03 9813 5999 or through email.