For
years the question of quality has always been
an issue in the dimension stone industry. Is "quality"
texture, color, ceramic, natural, defined, standardization,
legal, or perceived? Many people ranging from
architects to contractors, suppliers to fabricators
have asked what is quality? People have gone to
court to determine the quality of a stone or installation.
Many times people have perceived that the stone
is poor quality and this is why failures occur.
Failures in stone are usually understood to be
an issue of the quality of the stone. Others have
attributed the color variation of the stone as
a quality concern. When a stone has cracks, fills,
veins, or has mesh backing, or glued together,
or other natural inherent characteristics it is
considered poor quality. WRONG
Is
Quality: Texture?
The
first thing everyone must admit is that stone
is a natural product formed in the earth under
pressure for millions of years. We stone people
come along and take it out of the earth because
we think the color may make it sellable to an
architect or buyer for a specific application.
Thousands of millions of dollars are spent to
extract the stone and work it for resale. Some
people make money quarrying the stone only and
sometimes this is considered the most profitable
part of the stone business. Others make money
cutting the raw blocks into simple tiles and slabs.
Still other manufacturers work the stone into
intricate patterns, designs, statues, moldings,
columns, furniture, specialty items and so forth.
Everyone is looking for a way to capitalize on
the raw material and transform it into something
the buyers will want. Buyers are always looking
for different stones and have demanded so much
that there are now thousands of quarries trying
to satisfy every color palette under the rainbow
to give the buyers what they want. Some buyers
will find a stone ugly while others will find
it beautiful. The tastes of buyers in the world
differ so much that it is not easy to guess what
will sell or not sell. These tastes vary from
one section of the country to another.
In
past years buyers wanted mirror polished stone
for flooring. Today the trend is rustic flamed
or honed stone. Rustic may even mean that the
buyer wants cracks to appear in the stone to make
it look more aged and antique. Factories are appearing
now to specialize in the making of antique stone.
For years producers have fought to take a stone
which is natural and make it modern looking. Now
they are being asked to take a 20 million year
old stone and transform it into a product which
looks old naturally. This is true irony.
Suppliers
have worked with machinery manufacturers to take
the stone and treat the surface of the stone in
many different ways. Stone can vary with such
finishes as flamed, sandblasted, polished, honed,
acid washed, cleft, sawn, water jet, and liquid
antique to name a few. Each stone may flame or
polish differently. Some stones will not take
a mirror polish well. As it is the nature of stone
to have different degrees of hardness and abrasive
resistance and contain hard and soft spots within
the same face of the stone, it only shows that
the stone can vary in the degree of finish. It
is this natural difference that gives a specific
stone the warmth and texture that architects and
buyers want. It is the nature of dimension stones
to exhibit variation. A stone which is polished
may not appear to look similar to itself when
flamed.
Is
Quality: Color?
Buyers
have taste in colors that vary so much that no
one really knows what colors sell internationally.
Color is determined by the amount of certain types
of minerals or feldspars or impurities. Certain
colors that may not sell well in North America
do sell well in the Far East or Mid East. Buyers
have selected stone in the past due to the color
variation a stone portrays. Now some buyers want
the same stone but only 5% of the production as
they may not want to see all the color variation
but only a select portion of it. Some stones require
20 samples to show the color range while others
you can see the overall appearance with two samples.
The ability of a supplier to control the color
to the limitations and expectations of a buyer
varies. This limitation may be achievable or may
not. It may be a consideration of cost or time.
It may be limited to a smaller size. The limitation
of color in supply is more of a factor of the
supplier than the quality of the stone. In any
case, a buyer should never determine the selection
of a stone from a mere photograph or one small
sample.
In
a recent study in France on color it was noted
that the human eye can distinguish over 785 color
variations. Thus even the ceramic producers who
try to control production by color lots and mark
the boxes with color codes are themselves showing
the difficulty to match and control color. How
can natural stone be controlled in color?
Is
Quality: Ceramic?
Some
stone producers sense that the buyers are being
dictated by the ceramic industry. In ceramic the
color is matched very well to the buyers needs
and the consistency and uniformity of the product
is well known. How can buyers expect that
of a natural product like stone? Why even
select stone if you want a vinyl or ceramic look.
In fact, now the big push by ceramic tile producers
is to make ceramic tile look like limestone, granite,
and marble. The problem they have is to match
the beauty and warmth of natural stone. The ceramic
producers will keep searching for the ideal product
they can produce to look like stone which will
give them a larger share in the market taking
away sales of natural stone. Richard Dray of Richard
Dray Engineering calls this attempt by ceramic
producers as a way "to provide predictable patterns,
perfect color matches, reliable supply and known
physical characteristics more economically." This
attempt to duplicate natural stone is very difficult
in its entirety. However, since this is a buyers
market and there is so much competition many ceramic
producers will keep trying. They will succeed
eventually as this is a credit to man and the
innovations of technology.
Is
Quality: Natural?
What
makes the stones different? Some stones are different
because of the granular structure like dolomites,
whereas Calcite marbles have a mosaic structure.
The metamorphism of the stone causes certain impurities
such as clays and quartz to react with calcite
and dolomites to form minerals such as garnet,
talc and olivines. The presence of other minerals
such as iron oxide produces red colors; chlorite
and epidote a green color; and graphite a blue
color. Some stones are from mountain tops while
others are underground or from old river beds.
Some stones will have fossils in them showing
the true age of the stone. Some stones have open
seams or veins that open when exposed. A few factories
will leave these natural occurrences alone while
others will fill the voids or holes with matching
colored epoxies. Many stones have cracks or are
inherently weak and will break when put under
the pressure of the polishing machine so some
factories put a mesh backing on the stone to hold
it together. Many green stones warp when not under
the pressure of the earth. This is due to their
cellular structure. None of these issues deal
with the quality of the stone. Some of these issues
must be addressed however in the production or
installation of the stone and the buyers must
be aware of this as well.
"Marble
owes its beauty and strength to the skeletons
and shells of countless millions of tiny sea animals
called crustaceans and is made of calcium carbonate.
Onyx are calcium carbonates deposited by water.
Verde antiques are marbles made up chiefly of
serpentine, a hydrous magnesium silicate. There
are three major types of rocks quarried: igneous,
metamorphic, and sedimentary. Marble, quartzite,
gneiss, and slate are metamorphic. Sedimentary
rocks are shale and sandstone, while granite is
igneous rock usually containing quartz, feldspar,
mica. Limestone comes from sea shells and corals
whose chief by product is carbonate of lime and
is a sedimentary rock. Travertine is really a
form of limestone. Slate and shale have predominant
minerals such as mica, chlorite, and quartz."
There
are so many different stones with varying degrees
of hardness or abrasiveness that not all stones
polish with the same mirror polish that a buyer
may expect. Many stones have different degrees
of absorption which will affect the long term
maintenance of the stone or make the stone perhaps
not suitable for certain exterior applications
or flooring applications. Some stones will fade
in color when in direct sunlight; while other
stones will spall or chip or peel when water is
applied to them like Negro Marquina; while other
stones will effloresce when water is used on them
like some of the Taiwan green marbles. Some stones
such as slates or sandstone's due not split evenly
when cleft finishes are required so the variation
in thickness can be a lot more than expected or
the face of the stone can be more or less variation.
All these occurrences are natural and quality
is not an issue. There are over 5000 different
stones from over 34 different countries. The buyers
are strained to know all the variables about each
stone.
Is
Quality: Defined?
Defining
quality should be to understand what issues are
not quality concerns. Quality should not be considered
as the nature of a product to exhibit its own
characteristics. Natural stone can not be made
artificially or reproduced in a laboratory. It
is natural and this is why buyers have selected
it in the first place. The Marble Institute of
America years ago started to classify marble by
grades A-B-C-D as a soundness classification.
"A" was to mean a very consistent stone with a
sound structure which did not require gluing or
fixing. "D" stone was a marble whose characteristics
required sometimes gluing and exhibited a lot
more color variation. None of these soundness
classifications had anything to do with quality.
A "C" stone could be used on floors or walls and
once installed properly would perform its function
as well as a "B" stone. However, today many architects
are trying to define their needs as wanting an
"A" marble of which there are very few "A" marbles
in the world. In many architects minds they consider
"A" to mean quality for which this was never intended.
The elements of design are the line, color, value,
space, mass, and texture. The architect will use
these elements to design a building and select
a product such as stone to suit these elements.
As there are many design tastes there are also
many natural stones which can be selected to suit
most design elements. The oldest known examples
of architecture are in Egypt and are made of stone
blocks called pyramids.
The
market in stone has never agreed on defining quality
in stone. In past years, for example, I have spoken
with numerous producers or fabricators of stone.
In each case one claimed to produce better quality
than another producer. No one agrees what is a
quality polished edge or a bullnose edge. Each
producer says he can do a better job than his
competitor. Since the machines to produce the
labor items as well as the workers techniques
vary from shop to shop, it is easy to see this
contradiction in what is so called quality. What
is acceptable workmanship must be determined by
the buyer as it is in the furniture industry.
In furniture, there are different manufacturers
of sofas and perhaps one is better quality than
another, but who is to determine the standard
of quality and rate it or define it.
Is
Quality: Standardization?
Recently
Europe has introduced ISO 9000 which is being
implemented in many countries. It is trying to
define "Quality Standards" yet in the United States
this presently is called Q90 released by ANSI/ASQC
and is a complex set of requirements to help establish
a unified quality policy in manufacturing. However,
how this applies to the stone industry is obscure.
The system of ISO 9000 is primarily a paperwork
one in which the standards of management, principles,
marketing, procurement, test equipment, corrective
action, personnel, product safety are all quality
issues. No attempt has been made at defining the
quality of stone as it is natural. The procedure
a company follows to produce a product and sell
it and stand behind it are the real issues. "Quality
control is a system for verifying and maintaining
a desired level of quality in a product or process."
However, it does not define quality in stone except
to say it is "character with respect to grade
of excellence..." This ambiguity in terms of defining
quality is confusing as natural products such
as dimension stone has been used for exterior
or interior applications due to its quality which
really refers to integrity or the ability to withstand
the natural elements or man made elements.
Quality
has to be definable. A.S.T.M. defines in section
C119 standards for terminology in stone but says
nothing about quality. It further defines the
standards of testing stone and the results for
physical requirements as it relates to matters
which can be tested such as abrasion, compression,
absorption and so forth. These are all definable
and controllable. The results of such testing
can be used to define the integrity of the stone
for a specific application. Certain results of
testing can than be made to make sure the stone
will perform within minimum standards. These standards
set by A.S.T.M. are accepted generally as a guideline
only to what should be used as a minumum for a
specific application. If a stone does not meet
the standard it does not mean it can not be used.
It only means that engineers and architects will
need to determine the thickness, or anchoring
method, or sealant, or maintenance, or limitation
in size that will work with this specific stone
for their application. Stones, for example, with
higher absorption have been used on exterior high
rise cladding even though they have a higher than
acceptable amount of absorption. Further, the
amount of testing done on a stone during its manufacturing
process varies thus some stone may pass certain
standards while the same stone may not pass in
other areas. All the tests that may need to be
run on the stone are not necessarily performed
nor are the standards even addressed by A.S.T.M.
such as the affects of sun on coloration changes
on the stone. The industry is growing and learning.
In time more standards will be invented and need
to.
Is
Quality: Legal in Stone?
There
is a legal issue in the word "Quality". In old
legal documents it was called Caveat Emptor or
"Let the buyer beware". Since our economy has
grown we have become protective of the consumer
and thus the legal system has established not
only express warranties, that which is written
and defined on the product, but also implied
warranties, or that which implies a quality
of the product that makes the product suitable
for which it was sold. The U.C.C. or Uniform Commercial
Code states that "every sale implies warranties
such that the goods are fit for the purpose you
had in mind in making the sale and that if you
ordered from a sample or a description, what you
will receive is like the sample or is as it was
described to you." It is therefore up to each
sales person to know the product he or she is
selling and know where it should be used and where
it should not be used and how it will perform.
The samples shown to make a sale must represent
the material being sold. This, many times, is
most difficult for various reasons. Sometimes
this is difficult since some stones vary a lot
in color, or have holes, or carbon spots, or cracks,
or fills and therefore besides a sample a clear
written description should accompany the sample.
Quality
must be defined in workmanship of the stone to
assure the quality control as may be established
by such standard documents as the M.I.A. Design
Manual. In this manual you can refer to tolerances
in size or thickness, or to the installation method,
patching of stone, A.S.T.M. standards of stone
performance, warranty, and maintenance of the
stone. These have been defined and can be used
for reference. If specifications such as outlined
by the M.I.A. or A.S.T.M. are tied into the contract
of sale or purchase orders than perhaps their
is a legal basis to revert back to this document
as a way of stipulating the quality controls that
were to be expected. It is common practice that
most buyers do not presently do this.
It
should not be the place of the buyer to look at
stone and because it has natural flaws or not
the exact color they expected to imply the quality
is poor. There are selections many times within
a stone family that may give the buyer less or
more color variation. The natural flaws of a particular
stone are natural and can not be normally avoided.
In any case this is not a quality issue. It is
a selection issue. If the finish on the stone
does not match the sample then perhaps the quality
of workmanship was not controlled. Some stones
are difficult to polish evenly and with uniformity
as they may naturally have, for simplicity sake,
soft and hard spots. On filled travertine, for
example, to polish the face evenly and give a
mirror polish is impossible since the face is
stone and cement. Again this does not imply the
travertine is of poor quality. Some limestones
for instance have an absorption of 20%. This does
not imply a poor quality limestone, only that
it has high absorption. Knowing the weakness of
a stone will allow the buyer, architect, or installer
to know how to handle the stone for its intended
use.
Is
Quality: Perceived?
I
once visited a buyer who ordered Crema Marfil.
He was rejecting the Crema Marfil due to its poor
quality. Upon visiting the client we found out
his complaint was the stone showed too much gold
veins and had a slightly darker background then
he was used to receiving. The supplier and I studied
the stone and inspected the size, finish, packing,
uniformity etc. and found the stone to be of exceptional
quality. In reviewing with the client what he
wanted or expected, it was found that there are
3 distinct types of crema marfil. Some of the
marfils have a lighter background with light white
spots in it, which are very soft and eventually
crack, and with less veining. The soundness of
this stone is inferior to what he received. The
complaint strictly revolved around color and veining
and it was determined that in no way was this
a quality issue. In fact, it just so happened
that the representative of the stone association
from the area in Spain where this material was
quarried was in town. We brought this individual
back to see the product and told him the complaint
perceived as "the buyer said this was not
good quality". Immediately, without hesitation,
the representative stated the material was of
far superior quality. The point of the story is
that buyers do not always want quality or do not
understand themselves what is quality, but they
do know color. Color in many cases is why the
stone is selected, besides its texture, or finish,
or wear.
Conclusion
Therefore,
in conclusion, the industry must now define and
relate to buyers the knowledge about the stone
prior to selling it. Items that should be discussed
and perhaps put in writing are: quality, quality
control, color variation, durability, hardness,
absorption, warping, filling, cracks, spalls,
spots, veining characteristics, how to maintain
the stone, how to install it properly, and inherent
problems that can be foreseen in its lifetime
of use. Many times even the seller does not know
all the answers to these issues. However, if we
as a group of marble people expect to sell more
stone than we can not allow the caveat of "Buyer
Beware" or the buyers will eventually not wish
to buy stone. The word "quality" should sometimes
be referred to in the selling and the knowledge
of the stone and not the stone itself.
