Basic Knowledge of Stones
Web Page Clicks : 11/7/2008
Colors
As discussed previously, stone was formed from different types of natural minerals. Marble's main consistency is calcium. calcium carbonate is the natural source that bonds the stone. certain additive minerals blended into during formation to customize these brilliant colors. The additive minerals are also color developers present in granite and other natural stones.
Stone color Mineral
Black Biotite, Hornblende, carbon
Brown Limonite
Gray Variety of minerals
Green Mica, chloride, Silicate
Red Hematite
White Feldspar, calcite, Dolomite
Yellow Limonite
Mineral Mineral color
Augite Brown, Green, Black, Purple
Biotite Black, Brown, Green
Calcite Pearlenscent and Pale colors
Dolomite Colorless, Pink, Pale Brown
Feldspar Yellow, White, Pink, Green, Grey
Hematite Metallic Grey or Black
Hornblende Green, Yellow, Brown, Black
Limonite Black, Brown, or Yellow
Sulphur Pale Gold
Minerals have a variety of crystalline properties. A different has a different color. For instance, Augite (listed above) has different crystalline properties. Each property has its own color. Stones brilliant colors and various crystal formations developed when different mineral properties blended together along with the integration of temperature and pressure.
The veins and color grains of marble were liquid minerals that flowed through the stone when the Earth heated up. The intense heat softened the limestone to allow the liquid to flow through it. When the Earth cooled, the mineral flow stopped and gradually hardened to its state.
The delicate colors of stone often can altered by the improper use of cleaning chemical, mopping with dirty solution, using chemicals that are not designed for stone care, and sunlight can fade the color of natural minerals.
Reflectivity of Stone
Stone contains natural crystals. These crystals reflect light to provide a shine on the surface. When the crystal care dull, crushed, or broken, they cannot reflect light evenly. For Example, when the lens of a flashlight breaks, it cannot reflect the light that is being emitted form the bulb.
Polished stone floors become dull when heavy foot traffic along with sediment erodes the crystals. Normal footwear does not cause the main damage, sediment and grit do. The sediment and grit that lies on the stone surface is the main enemy of stones crystal. The damage to the crystals occurs when the pressure from the shoe forces the sediment to abrade or fracture the crystals.
The only safe way to restore and sharpen the crystal is to polish them with diamond abrasives or polishing powders. The life span of crystal can be extended can by administering a through dust mopping program with proper moping and maintenance system. Extensive entrance matting is extremely important because it keeps exterior sediment from entering a building.
The Hardness of Stone
Marble is a relatively soft stone. On a measurement of hardness of (MOHS), marble is approximately a three out of ten. Marble is made of calcium, just like your teeth. If you eat something to hard you will break your tooth. If you eat a lot of sugar you will get a cavity. Stone reacts the same way. If an improper chemical is applied to the surface, corrosion will begin to from cavities in the stone.
Listed below is the famous Measurement of Hardness (MOHS) Scale for stone. This is a guide developed in the 1800's, which helps evaluate the strengths and weakness of the stone being used. For example, softer stone would require less active chemical and a more frequent dust-mopping program.
Measurement of Hardness Scale
10 Diamond
9 corundum
8 Topaz
7 Quartz (Granite)
6 Feldspar (Granite)
5 Apatite
4 Fluorite
3 calcite (Most Marbles)
2 Gypsum
1 Talc
The objective of the MOH's Scale is to measure stone resistance to hardness. When sediment and grit harder than the surface, they will scratch and harm the stone. For example, a piece of hard plastic is about a 2.0. It will not scratch #3 calcite (Marble). However, a piece of sand that measures a 6, will scratch #3 calcite but will not scratch #7 Quartz which is Granite. The harder the stone, the more resistant it is to abrasion. Exterior sediment that is tracked in to buildings approximately measures from 3.0 to 7.0.
Understanding Stone Maintenance Chemicals
In the stone maintenance industry there are two types of chemicals that are utilized, water-based and solvent-based.
Solvent-based chemicals do not contain any water do not register a PH balance. These ingredients are only soluble in other solvent. Some examples of solvent chemicals are paint thinners, most penetrating sealers (impregnators), D-Limonene, and alcohol.
Water-based chemicals are chemicals that contain water and have a PH balance. chemicals mixed in water are soluble in water. There are a water-based chemical such as neutral cleaners, ammonia, bleach, and most chemicals that have a PH balance.
In order to determine the different between solvent and water based chemicals, read the Material Safety Data Sheet (MSDS). Most solvent have flash point and can ignite. Most water-based chemicals do not have a flash point unless contain a solvent ingredient to add strength to the product. For example, many degreasers contain D-limonene. In most stone care situations, if a stain or coating is water-based, then water-based chemicals are needed to remove it.
Listed below are samples of the two types of chemicals:
Water-Based Solvent-Based
Alkalis D-limonene
Acids Alcohol
Hydrogen peroxide Siloxane
All purpose cleaners Acetone
Glycols Mineral spirits
It is advisable to use water-based chemicals. The reason is due to the environmental concern that solvent-based chemicals are harmful to our environment. Water based chemical are usually more user friendly. Remember to always wear proper protective gear when using any chemical and them all out of the reach of children.
Understanding PH Balances
PH is a unit of measure to determine the alkalinity and acidity of a solution. PH has been defined as either the "power of Hydrogen" or "Pre-existing Hydrogen". It is rated on a scale of 0 to 14. 0 to 6.5 being acidic (Hydrogen) and 7.5 to 14 being an alkali (Hydroxide). 7 being neutral.
Acid Neutral Alkalis
Acid Bowl cleaners Strippers
Vinegar Degreasers
Most fruit Juices Ammonia
Alcoholic beverages Most all purpose & household cleaners.
Many household bathroom cleaners Dirt and soil Many natural stones
Most stones used today are sensitive to both acidic and alkali cleaners. One reason is due to the fact that most stones are classified as hydroxides, which classifies them as natural alkalis. Acids will burn most stones by dissolving the bonding agent that together. Alkalis usually do not damage stone as quickly, however, they will cause deterioration.
The corrosiveness of acids cannot always be measured with the pH scale. In most instances, the lower the pH number the stronger the acids. A solution with a pH level of 1 is usually stronger than a solution with a pH of 4. However, there are some acids with a higher pH that are stronger than an acid with a lower pH.
On the alkali side, the higher the pH number the stronger the alkali should be. A solution with a pH balance of 12 is usually stronger than a solution with a pH of 9. When using an alkali cleaner, never use hot water because it may create a stronger alkali with adverse affects.
Understanding pH balance will help select the proper chemicals that can be used on stone. However, a main factor to remember when selecting a stone maintenance chemical is the activity level. For example, most neutral cleaners have a pH balance of 7; however, some neutral cleaners are stronger than others because they have higher activity levels. There are many neutral cleaners that are not active enough to thoroughly clean a stone's surface. There are also an abundance of neutral cleaners that are too active for stone to endure.
Understanding the Stone Maintenance Cycle
Stone is a neutral material. It should be taken care with proper maintenance procedures. Once the stone is installed, it will always go through a natural life cycle, precise maintenance schedules must be developed to care your type of stone.
Two main factors that should be considered when designing a maintenance program are the hardness and absorbency of the stone. These factors will help decide which chemicals, pads, brushes, and equipment are necessary to maintain the stone.
The Stone Maintenance cycle is comprised of three segments:
I. Preventive Maintenance
- Protecting the interior of the stone with a Penetrating Sealer.
- Proper walks-off entrance matting.
- Understanding your stone, chemicals, and procedures.
II. Maintenance
- Dust Mopping with clean rayon mops.
- Properly laundering and caring for maps.
- Wet mopping with a mopping program.
OR
Automatic scrubbing
- Repairing pits and cracks with epoxy or glues.
- Prompt spill pick-ups to prevent etching and staining.
- Powder polishing to receive polished finishes.
- Reabsorbing stains with poultice powders.
III. Restoration
- Resurfacing the stone with a diamond abrasive program to remove scratches, abrasions, and traffic patterns.
- Deep cleaning the pores of honed, flamed, or ground floors. Tag:Basic Knowledge of Stones
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