The term granite is derived from the
Latin word “granum” which means ‘grain’
due to its granular nature although for the Italian term
of granite is from the past participle of granire which
means to granulate or make grainy.
Granite is a very hard, crystalline, igneous rock primarily
composed of feldspar, quartz, orthoclase or microcline
accompanied by one or more dark minerals. It is visibly
homogeneous in texture. It is the most common plutonic
rock of the Earth's crust, forming by the cooling of magma
(silicate melt) at depth.
Large granite bodies may have formed within earth’s
crust by intrusion of new magma or by the re-melting of
igneous varieties of crustal rocks. The evolutionary history
of granite can be revealed by examining the chemistry
of successive layers of its large constituent crystals,
notably zircon. Granite is formed by the recycling of
deep crustal rocks as mantle magma rose through them,
rather than by re-melting the ancient, shallower crust,
as was widely believed.
Granite is typically medium to coarse grained, occasionally
with some individual crystals larger than the groundmass
forming a rock known as porphyry. Granite can be pink
to dark gray or even black, depending on their chemistry
and mineralogy. Outcrops of granite tend to form tors,
rounded massifs, and terrains of rounded boulders cropping
out of flat, sandy soils. Granite sometimes can occur
in circular depressions surrounded by a range of hills,
formed by the metamorphic aureole or hornfels.
Granite is nearly always massive, hard and tough, and
it is for this reason it has gained widespread use as
a construction stone. The average density of granite is
2.75 g•cm-3 with a range of 1.74 g•cm-3 to
2.80 g•cm-3. The word granite comes from the Latin
granum, a grain, in reference to the coarse-grained structure
of such a crystalline rock. For this reason granite is
used as a building material in the form of granite tiles
and granite slabs for wall cladding, roofing, flooring,
a variety of other interior and exterior applications
and especially for counter tops, kitchen work tops and
vanity units and is the most popular material for monuments
and memorials. Granite has a prominent place among dimensional
stones on account of its hardness, resistance to weathering,
capability to take mirror polish, fascinating colours
and textural patterns.
Despite being fairly common throughout the world, the
areas with the most commercial granite quarries are located
in the Scandinavian Peninsula (mostly in Finland and Norway),
Spain (mostly Galicia and Extremadura), Brazil, India
and several countries in the South end of the African
continent, namely Angola, Namibia, Zimbabwe and South
Granite is an igneous, magma-formed rock that is generally
made up of quartz, feldspar and mica. These minerals combine
in varying percentages that account for the color, veining
and crystallization patterns that make each granite deposit
— and therefore customized countertop — unique.
Other minerals, such as magnetite, pyrite, garnet and
hematite can occur in much smaller amounts, and as such,
it is these different combinations that create the wide
range of granite varieties that are available throughout
Mining & Processing
Granite is quarried across the globe since there are very
few quarries which have mining machinery, mining for granite
is a manual job which uses hand chisels and hammers for
Years ago, excavating granite was a timely, laborious
process that included the use of a significant amount
of explosives and a lot of manual labor in the drilling
process. Today, diamond wire saws and slot drilling are
the primary activities used to complete the job, making
granite more economical for consumers, as well as a cleaner,
safer and significantly less labor-intensive excavation
Granite quarry is a pit or some open excavation from which
granite is obtained. To obtain granite from a quarry digging,
cutting or blasting process is used. This process of obtaining
the stone is called quarrying. Once quarrying is done,
the processing of granite starts.
Granite quarries are laid out based on the direction in
which the granite will break the easiest, providing the
maximum benefit that can be attained from the natural
seams and structure. By using these natural seams, the
maximum yield can be obtained from the quarry deposit,
thus reducing the amount of stone produced that is not
suitable for use as dimensional granite.
The types of natural fractures that can be seen in a granite
deposit are based on their relationship to the flow lines,
as well as the surface of the granite deposit. Sheeting
joints run roughly parallel to the topographic surface
at various levels beneath the surface; longitudinal joints
are steep cracks that run parallel to the flow lines;
while cross joints are perpendicular to the flow lines.
Granites are now mined in most of the Indian states for
use as construction material and road metal but production
of dressed granite blocks and slabs from Andhra Pradesh,
Karnataka, Rajasthan and Tamil Nadu are highly priced.
In India there are 43 granite processing units of which
12 are in Andhra Pradesh, 13 in Karnataka, 3 in Rajasthan,
14 in Tamil Nadu and 1 in Orissa.
The recovery of marketable grade granite is reported to
be 32 to 40 per cent in Karnataka, 25 to 75 per cent in
four quarries around Jalore, the main granite mining centre
of Rajasthan, and 20 to 40 per cent in Tamil Nadu.
Over the years, granite has developed from a largely structural
material affordable only to the wealthy, to a stone that
has numerous applications — countertops quickly
becoming one of the most popular — and greater availability
and mass appeal. One of the reasons for this increase
in accessibility is the advance of technology used to
quarry the stone.
With new technology it minimized the costs thus bringing
granite into homes all across the world. Whereas in the
past, excavating granite from a deposit required an elaborate
process of drilling, pounding, sawing and blasting, now
— with the use of diamond wire saws, which look
like wires, but are covered in diamond segments —
quarry workers are able to saw whole blocks of granite
in a faster and more streamlined manner.
Granite is available in a wide variety of colors, including
white, black, pink and red. The varying percentages of
quartz, feldspar and mica account for the rock's color,
veining and crystallization, making each granite deposit
unique. The high presence of quartz can account for many
of granite's color variations, as quartz can be milky
white, rose, smoky, yellow or amethyst. Feldspar, another
one of granite's main minerals, can account for a glassy
white, blue, green or red appearance. Finally, mica can
contribute to a black, green, red, yellow or brown appearance.
- Europe: Austria, Belgium, the Czech Republic, Finland,
France, Germany, Italy, Norway, Portugal, Sardinia,
Spain, Sweden, Switzerland, Venezuela
- Africa: Angola, Egypt, Madagascar, Namibia, Nigeria,
- Asia: China, Egypt, India, Iran, Saudi Arabia, Sri
Lanka, Taiwan, Thailand, Turkey, Ukraine, Vietnam
- Architectural accessories
- Interior accessories
- Building stone
- Appropriate Finishes
- Bush hammered
- Sawn (rough)
- Average MOHs Hardness: 7
- Average Absorption Rate (%): .13
- Average Bulk Density (pcf): 172.8
- Average Compressive Strength (psi): 23,300
- Average Modulus of Rupture (psi): 1,855
How Granite Slabs are Created
||Chinese man working in a granite quarry
|Working in a quarry in India
||Mining in India –Old times
Granite is more than just a pretty face. The stone is
second only to diamonds in hardness, which accounts for
the effectiveness of diamonds in facilitating the quarrying
of the natural stone. It is granite's toughness and durability
that make it such a desirable countertop material. It
won't break or crack, and it is virtually scratch and
Cutting granite at the quarry
Once the granite is removed from the earth, it needs to
be cut to size accordingly. This is typically done with
wire saws that are often treated with a varying range
of abrasives from sand to aluminum oxide to diamond, along
with water which acts as a coolant. Other types of cutting
devices are often used in tandem, or in the absence of,
these wire saws. Water jet cutting, for example, uses
a focused, high-pressure stream to cut stone along specified
cutting lines. Once it has been established that the granite
blocks are to be used for countertops and tile, they are
cut and polished into the familiar forms for these purposes.
The granite tile and slabs are calibrated to ensure that
the thickness of the granite is uniform and gauged to
make sure that they are square; tiles are beveled to produce
their smooth edges. Once this part of the process is completed,
they are ready for your project.
There are four operations that are involved in the processing
of granite. They are:
• Surface Grinding and Polishing
Stone dressing: once a block of granite has been broken
down to the appropriate size required, the sides have
to be roughly smoothed off before polishing can begin.
Stone dressing was usually carried out at stone-cutting
and polishing works, rather than at the quarry itself.
Originally, rough dressing was done with a blocking hammer
or a dressing pick, with puncheons and chisels for finer
work. A more efficient dressing tool was the bush hammer,
or patent axe.
Cutting of granite blocks into slabs was once a laborious
process taking months, using an iron saw with sand and
water as an abrasive. With the invention of chilled iron
shot (small pellets of iron) and the use of steel saws,
the cutting time was reduced to days. The dressing process
left a relatively smooth surface which could then be polished.
During the 1960s, endless wire loop saws superseded the
old frame saws thus diamond tipped circular saws have
also been used for many years since it leaves a surface
sufficiently smooth as to require no further polishing
The rough blocks arriving at the stone yard from the quarry
are irregular in size and shape is inspected to identify
the most efficient way to cut them into slab form while
Once the initial inspection is complete, the block is
primarily sawed into slab form by means of large circular
diamond-tipped blades, wire or monoblade saws which cut
one slab at a time or by a frame saw with multiple blades
that cut each block – depending upon its size –
in a single operation into a number of slabs.
With this operation the thickness of the block can be
varied to suit the finished stone it is being cut for,
and it is only when the block is opened in this way that
any internal defects can be discovered. It is important
to remember that stone is a natural product and that colour
and veining (figuring) may also vary throughout a block
or from block to block and result in some slabs being
The next phase – secondary sawing – consists
of cutting the slabs into dimensioned ashlar. The machines
used are usually computerised bridge saws with circular
diamond blades ranging in diameter from 600-1200mm and
can also have tilting heads to provide angled cuts.
The resulting ashlar is coded ready for palleting or sent
to the mason workshop for other masonry work such as broaching,
droving or stugging to take place. In the second of these
options slabs can also be cut to sizes and shapes that
can be moulded by hand or, equally common today, by means
of lathes profiling and water jetting machines (these
machines are mostly controlled by computers).
The stone that passes through the lathes, profiling and
water jetting machines can either be returned to the secondary
saws to be jointed or moved to the banker area for the
masons to carry out further work such as returning moulding,
sunk mouldings or to cut out moulded brackets in a cornice
course. Following the completion of work to each stone
it is checked for quality and any defects before being
polished, palleted and ‘shrink-wrapped’ ready
for delivery to site.
The banker area is where time-served masons and apprentices
using traditional tools such as mells (mallets), teeth
tools, chisels, etc. carry out work that cannot be undertaken
Nowadays most of their chisels have tungsten instead of
steel tips and – instead of employing the blacksmith
of former years – are sharpened by use of grinding
wheels. The masons may now also use compressed air tools
and angle grinders along with drilling and coring machines.
Dressing of stone left a roughly flat but uneven surface;
polishing produces a smooth, even shiny surface. For thousands
of years the only way to polish stone was to rub one against
another, using sand and water as an abrasive. Polishing
machines were introduced in the early nineteenth century.
Flat iron rings were turned by hand over a dressed surface,
using sand and water as an abrasive. Steam power for turning
the iron rings was introduced in 1830s.
In the 1880s the Jenny Lind polishing machine was introduced
(the machine so called from its humming noise, which was
likened to the Swedish singer of that name).
This had a steel ring - shooting ring - which rotated
over the dressed stone surface, iron shot and water were
used as an abrasive. Finer polishing stages used carborundum
With modern saws leaving smoother finishes, the shooting
process is unnecessary, and carborundum polishing can
begin immediately. A modern version of the Jenny Lind,
the Seaton polisher, has four small rotating solid carborundum
heads and is often fully automatic.
A building’s architectural expression can be greatly
enhanced by the choice of surface finish and in the case
of natural stone a variety of considerations apply, including
the function, type, and hardness of the material as well
as the aesthetic effect desired. Greater awareness of
the range of light and shade effects possible on different
stone types and of the techniques available to draw out
the unique qualities of each has increased demand for
manually dressed stone, and this traditional process has
become easier and quicker with new types of compressed
air tools and machines.
Depending upon a stone’s intended application, material
strength and the minimum thickness needed to withstand
differing processing pressures, it is now possible to
apply all kinds of finishing techniques. Final surface
character is determined by the fineness of the applied
finish used and can bring out a stone’s mineral
content, colour, texture and structure.
Not all the listed finishes can be applied to every stone
type, e.g. only sufficiently hard and dense stones such
as granite can have a polished finish (the finest), but
honed and fine-rubbed finishes are achievable
Edge/Cutting & Trimming
Carving of granite was always a long difficult process,
not speeded up until the introduction of compressed air
drills with tungsten tipped chisels. Polishing of detailed
intricate carvings was carried out by rubbing the surface
with stone using sand as an abrasive. When chilled iron
shot came into use, shotting fiddles were used, with emery
and tin oxide putting for later polishing stages.
Grading Granite Slabs
|Gold & Silver
|Labareda Gold/Lapidus Gold
|Golden Musk/Verde Fantastico
||Blue Pearl GB
Granite is a natural stone which is quite unique since,
unlike man-made materials, these natural stones will show
a variation in colour and texture. With this in mind,
the grading process is based on the variation of colour
and characteristics of the granite.
• First Choice Quality—here the granite is
what the name says, the finest quality ever. With the
first choice quality granite upon receipt one only needs
to do is cut the granite slab to size, profile, etc during
the fabrication process. The polishing process should
no show any visual defects and be of a high gloss surface.
With first choice quality granite during the fabrication
process the amount of waste material is quite low.
• Commercial Quality—typically with this grade
the granite will not polish quite as well and obvious
visual defects such as blotches or small natural hairline
cracks are present. However, a good fabricator and sawyer
will have the ability to use the granite slab to its fullest
• Second Quality—this grade of granite typically
is used for larger contract or larger projects where the
granite slabs are to be cut into smaller modules. The
granite will have several repairable natural defects along
with blotches. However, for the experienced fabricator
this is a smart way to reduce costs on raw material although
it will take more time to make the best granite slab.
• Caveat Emptor - Buyer beware!
• Depth—the depth of polish should be a minimum
• Length / Width—the granite slabs are given
a 2 cm allowance from the narrowest point of measurement.
• Measurement—keep in mind that granite is
a natural stone thus you may not be able to obtain a guarantee
in length and widths. You should always be offered the
estimated slab measurements prior to sawing the blocks
in order for you to decide if the slab is suitable for
• Pre-cut Slabs—granite slabs which are a
stock item should have already been measured and are ready
to ship. Pre-cut slabs can be inspected independently
and verified if so required.
• Resin Filler—granite slabs which contain
a natural open-veined formation will have a suitable resin
filler applied to them.
• Slab Thickness—granite slabs sawn with a
gang saw will have a tolerance of +/- ½ mm to the
thickness of the granite slab. Along with this the polished
face will be level.
• Tile Thickness—granite slabs fabricated
for tiles will be produced to +/- ½ mm of the desired
• Colour Enhancer—unless specifically requested
granite slabs do not use colour enhancers.
Typically a large number of companies use flatbed trucks
to transport granite slabs since the granite rock slabs
vary in weight from hundreds to thousands of pounds. The
granite slabs are transported vertically on storage racks
which are typically constructed of metal and/or wood in
an A-frame structure. The granite slabs are then strapped
in onto this A-frame structure and loaded onto the flat
bed by the distributor. The slabs may be secured transversely
and vertically to the frames prior to loading. Shoring
prevents the frames from moving vertically and tipping.
Direct lashing is used to prevent any lengthwise movement
of the slabs.
Transporting granite slabs can be a difficult process
since the loads can shift or if the granite is being transported
by train the tracks can actually become deformed or fail.
>>Preparing granite slabs for shipment
>> Once the granite has been cut, trimmed and polished
it is prepared for delivery. The manufacture can utilize
trucks, sea or trains as a method of getting the granite
to the customer.
>> The granite slabs are packed in strong weatherproof
wooden crates which have been fumigated. Typically the
crates can bundles of 8 – 10 ¾” granite
slabs having the capacity to hold 400 - 450 square feet.
Each bundle weighs 2.6 tons, or 5,700 pounds. Every slab
is protected by a thin plastic sheet placed between slabs
along with a piece of wood which is placed beneath the
>> The granite slabs are now ready to be transported
to the nearest shipping port for subsequent delivery to
Manufacturing Granite Worktops
Granite stones from the quarry look like a huge boulder
yet the granite slab undergoes several processes turning
the granite slab into a beautiful piece of stonework for
you kitchen worktop.
Transporting the granite slab
Typically one views the transport of the granite stone
as just loading it onto a truck and it is on its way to
the manufacturer. However, unprocessed granite stones
have a tendency to rub against each other thus grinding
each other to pieces while in transport. If the granite
slabs are not transported correctly the manufacturers
could end up with a pile of stone dust.
The hauling trucks are fitted with containers which keep
the granite stones packed in tight preventing movement.
Once they reach their destination the granite slabs are
gently unloaded with huge cranes.
Precision cutting is the key element which is required
to cut the granite stones which stone-cutting saws are
used. For worktops, the granite slabs are cut into slabs
1 – 2” thick which gives stonecutters and
fabricators more room to work with. The stone-cutting
saws are typically diamond-tipped to prevent a sharp,
hard cutting edge. Once the slabs have been cut, pressurized
water is used on the edges of the granite stone. This
process will refine the granite stone along with removing
the coarseness around the granite slab’s rim. These
water jets used for cutting stone maintain a water pressure
of over 100 lbs per square; the water itself travels over
200 miles per hour.
The granite slabs are ready for finishing once they have
been cut to the correct shape. This process involves sanding
the piece with several buffers and different grades of
sandpaper. Imagine doing this by hand, sounds tedious
thus many manufacturers have machines to do this for them.
The profiling process will create the shine for which
the granite worktops are valued.
Typically an unfinished granite worktop will chip and
break due to imperfections on the surface so profiling
is used to help harden and clean the surface of the granite
The exact customization is based on what the granite piece
is actually going to be used for, once the customer has
given their specifications the piece is finely detailed
prior to its being ready to be used. A typical kitchen
worktop should have a hole for the sink cut out into the
center of the granite worktop. Again, after the cut the
rough edges will again be sanded away. Clips and support
pins for the sink itself are also added onto the kitchen
Some granite worktops do not require a hole to be cut
however; some customers prefer more texture in their granite
worktop. At this point the master craftsmen use a hammer
and chisel to create curlicues and geometric designs along
the edge or in the center of the piece.
Finally, the piece is wrapped in bubble plastic, secured
with duct tape, and is ready to be transported and installed.
The entire process, from unrefined stone to finished usable
countertop, usually takes less than a day, with pieces
that require heavy detailing taking more time.
Granite worktops are crated and shipped upright and must
be unloaded and unpacked upright. You will also never
want to carry the granite worktop flat, always in the
upright position otherwise you will risk fracturing it.
However, nothing spruces up a kitchen better, faster,
and easier that a new granite worktop. Bring a sketch
with very accurate dimensions or eliminate any risk by
taking advantage of the dealer's professional measuring
services. Once the top has been cut to size, you can begin
>> Straight edge
>> Spirit level
>> Drill bits with suitable drill for granite
>> Suitable saw (Hand held) for granite
>> Jig Saw (for wood)
>> Polishing heads
>> Adhesive (Araldite / Polyurethane)
Prepare the base
—using a tri-square
make sure the cabinet corners are square and level by
using a spirit level. The existing cabinets should be
firmly fixed in place before the installation of a granite
—prior to actually
installing your new granite worktop you need to make the
sink cut which can be done for a drop-in or under mount
sink. To do these mark the granite surface using the manufacturer’s
template leaving sufficient margin from the front to the
rear edge. Carefully place the granite slab on a workbench
and cut the granite slab along the marking. You may want
to do this step outside due to the excess dust it will
create. Finally polish up the inside edge of the granite
slab along with the sink top and the granite slab is now
ready for installation.
Laying the granite slab
against your base cabinets in order to obtain the correct
measurements to cut your new granite slab to the correct
measurement. Now place the granite slab on the base aligning
it square to the front end of the cabinet. Use a level
and adjust as necessary, if needed. Remove the granite
slab, apply glue to the cabinet frame and place the granite
slab on the cabinet base and allow it to set. If you need
to make any adjustments do it prior to the glue hardening.
Use steel brackets to secure the granite worktop to the
frame from underneath. Continue this process for all other
granite slabs you have to install.
Butt the seam joints
which are to be seamed must be thoroughly cleaned along
with making sure that the edges are straight and square
to the granite worktop. Align the edge and surface of
the two sections, using araldite for the seam joint and
tightly butt the granite worktops. Use mineral spirits
to clean the surface of the joint to remove any excess
adhesive. You may want to use clamps to bind the two granite
worktops together during the hardening process removing
them immediately when the araldite has hardened.
Sealing the worktop
—now that the
installation is complete the surface should be sealed
in order to protect the granite worktop from staining.
To do these apply the sealer on top of the surface allowing
it to ‘sit’ for 10 minutes. After 10 minutes
clean up the excess sealer with a clean cloth according
to the manufacturer’s recommendations. Allow the
adhesives a minimum of 48 hours to dry then apply a second
coat to protect the granite surface against bacteria and