Many different types of stone, including marble, granite, limestone and quartz (re-constituted stone) are used for furniture.
Concrete is also used, and has similar properties to many types of stone. Terrazzo is made from around 70% marble chips, 30% cement, so behaves most like marble. Stone is durable, but it is also porous and the more porous it is, the more likely it is to stain. Some types of limestone, for instance, with more open pores are particularly vulnerable. Some Granites, on the other hand, hardly stain. To counter this, stone surfaces tend to be sealed (and sometimes lacquered). Over time this seal will lose its protective capabilities.
What is Acid Etching?
Acid etching is a reaction between the acid in the liquid and the table top. As calcium is a major mineral content of marble it reacts with acidic liquid. Effectively the acid from the liquid matts down the polish level on the marble and is seen as a ring mark - This is not staining and over a period of time the marble develops a patina.
The most common causes of damage to stone surfaces
- Permanent stains from acids in foods such as tomato, mustard, fruit juices, wines and coffee. This is a common problem with red wine vinegar where oysters are served. It etches strongly and leaves a pinkish colour. This particularly applies to carrera marble and limestone.
- Etching from using the wrong cleaning products, such as scouring creams, other abrasive cleaners and acid-based products such as hydrogen peroxide or bleach.
- Chips and scratches from knocks, particularly on straight edges. This particularly applies when tables are pushed together and the tops are knocked.
- Seals on stone being damaged by excessive heat causing a light brown stain – this can be avoided using mats.
Beware Hot metal tea and coffee pots.
When tea or coffee are served in pots which don't pour well the liquid runs down the spout and collects on the bottom of the pot. When the pot is put back down on the table top the liquid is trapped underneath. The heat of the pot is forces the liquid into the table top because heat repels liquid.
Wipe with warm water and soap, liquid detergent or Relay Spray (use a soft brush if necessary). Stone surfaces can be polished using standard polishing products.
Difficult stains (maybe ink, wine, etc) can, with care, be cleaned off using white spirit (don’t use on concrete) or a cleaning product such as Vanish Oxi Action Stain Remover. White spirit is also useful in removing grease and oil marks. Try to avoid concentrating on a single area, which may create a contrasting lighter finish. We strongly recommend first testing the cleaning on a non-visible area such as the underside of a table. It may be necessary to re-apply a stone sealer (or, for concrete, a wax sealer) after deep cleaning.
Example: Wine stains on a marble table top
Cleaning with white spirits will remove the stains but will leave the top looking dull and tired as the white spirit has matted the tops, levelling the polish levels . A sealant will need to be reapplied to acheive a nice bright finish.
Applying a penetrating seal is the most effective way to protect a stone or marble surface. We recommend using a product such as sealers by Premium Stone at least once a season, following product instructions.
Take great care moving tables with stone tops; the bases can come off as the top-to-base fixing tends to be adhesive rather than screws (to avoid screwing into stone). When moving tables with stone tops, take particular care and lift from their bases.
Free Furniture Care & Maintenance Guide
Get more from your contract furniture by caring for it properly. Download our Furniture Care & Maintenance Guide to learn how to make your furniture last longer in a hospitality space.