Stone Informational Addendum
The utilization of natural stone specimens in residential or commercial applications present some natural and distinct problems. Different types of stones are susceptible to damage by natural and man made hazards. The following information is meant to keep you informed as to the problems that can and do occur with your stone type even with introduction of preservation. Your stone classification has been checked for your easy reference. Please read it carefully for your protection.
Shale stone is formed when mud like substances are compressed and then dried over a long period of time. This formation is subject to disintegration by a simple excess of moisture by a positive or negative side influence. This means that this category of stone has the possibility of reverting back to its original form of mud.
Sandstone is formed when sand and an alkaline settling is formed under pressure and joined at the uppermost surface of the earth. The simplistic result is glued sand particles that form stone. This alkaline “glue” is subject to acid attack. This can come from the ground soils or can come from being acid washed or being next to an acidic source like a swimming pool or the spilling of sodas, wine, coffee, champagne, etc. When this attack occurs the stone will revert back to its natural state…sand.
Slate is formed when wide ranges of minerals are compressed in layers near the earths’ surface over time. Though somewhat similar in formation to sandstone, these layers are distinct and time marked. Due to this type of formation, slate is prone to “cleft plane spalling” which is a process where layers separate from the main stone body. Combined with the soft character of slate, these layers can be separated by walking on the surface, dropping or moving items over the surface or excessive moisture presence. Due to its’ soft nature, slate is also prone to scratching.
Flagstone is formed when minerals and chemicals are compressed just beneath the earths surface. Flagstone is quarried and split to be placed into pallets for shipping. Different types of flagstone have varying strengths depending on their mineral makeup. Flagstone “shales” like slate, but not nearly as much. It is an absorbent stone and will separate if exposed to high moisture, but some shaling is natural to this stone.
Limestone is formed when sea beds dry up in layers over time which results in the decay of aquatic organisms. This sedimentation process over time and intense pressure yields limestone. Limestone is basically calcium carbonate which is a pure form of a very soft alkali. When this stone is exposed to acids ie; the spilling of sodas, wine, coffee, champagne, etc. the resultant condition is a etch mark that needs to be polished to be removed. Repeated acid or high moisture attack can result in permanent and irreversible stone damage and color change. This stone class can scratch easily under normal wear.
Travertine is formed during the metamorphic change from a limestone like state to a marble. The result is a marble that is characterized by holes within its structure. These holes are filled at the quarry, but do tend to pop out over time and will need to be repaired. The stone is also susceptible to acid attack ie; the spilling of sodas, wine, coffee, champagne, etc. The result of such an attack will leave deep burn “etch” marks that will require mechanical removal.
Marble is formed when the metamorphic change has been completed from limestone to travertine to marble. The same minerals are present throughout the three stones except marble is exposed to much greater time and pressure than the others. Marble can be soft and prone to easy scratches. The stone is also susceptible to acid attack ie; the spilling of sodas, wine, coffee, champagne, etc. The result of such an attack will leave deep burn “etch” marks that will require mechanical removal.
Granite is formed when a quartz structure has hot magma extruded between it under intense pressure and heat. Granite, though incredibly hard, can fracture when struck by a hard or sharp object. It will also naturally absorb oils which can and will change the color of the stone.
Quartzite is formed when quartz structures of sandstone are subjected to intense heat which eliminates the impurities found in sandstone which joins the crystalline structures into one pure formation. This metamorphic process creates one incredibly hard structure whos’ primary enemy is man. Quartzite is primarily hydrophobic, but does take in organic and inorganic hydrocarbon based materials which subject the stone to staining. The mica portion of the stone does tend to flake in very small, 2mm, areas and does not generally weaken the stone.
This information has been provided to you by AER, Inc. to assist you in keeping better informed about the surfaces you will or already have on your property. After 16 years of professional masonry restoration and preservation experience we have learned that open communication and a clear understanding of surface limitations with our clients is the best foundation to a lasting professional relationship. We would welcome any specific questions regarding your stone and we pride ourselves on always being an accessible resource for all of our clients.
Information provided by American Environmental Recovery, Orange County 714-891-4009