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Roger Weller, geology instructor

wellerr@cochise.edu

Headstones
by Paris Reynolds
Physical Geology
Fall 2007
 

The Last Decision Youíll Ever Make: Choosing a Headstone


          
 Tombstones, gravestones, and headstones are important pieces of history that serve as markers and memorials for loved ones. The purpose of a headstone is to mark the ground where a soul has gone to rest and bear the name and lifetime of the deceased for all to know and remember. The message is important, but for the message to endure, the material must remain. Thatís where geology comes in. Which materials are most aesthetically pleasing? Which materials will resist weathering? Which materials can be carved and shaped well? Which materials are least expensive? In short, what is the best stone to make a headstone?

 

(marble headstone) Public Domain

 

            Originally, humans marked a place of rest with a simple fieldstone. Natural stones like granite, sandstone, slate, marble and limestone have all been used throughout history. The most popular stone today is granite.
 

(Granite headstone) Public Domain

 

            Granite is a course grained, igneous rock made by the slow cooling of silica rich magma. It generally consists of mica, feldspars, and quartz. Sandstone is a clastic sedimentary rock of cemented sand grains of mostly quartz. Slate is a metamorphic rock produced by the heating and or compression of shale, a sedimentary rock made up of mostly clay. Marble is also a metamorphic rock formed from recrystallized limestone. Over 300 varieties of marble are recognized. Finally, limestone is a chemical sedimentary rock made of calcite. The material that makes the best headstone depends on personal preference and personal priorities.

 

(Granite)

 

            In terms of color, granite, with its shining mica, salmon feldspars and semi-transparent quartz, is a beautiful choice. Marble can also be very beautiful. The most popular color of marble for a gravestone is a bright white. Organic and Iron compounds give marble a variety of colors. Because it is a metamorphic rock it forms different designs like band, swirl and breccia patterns. Limestone, and sandstone are typically dull and lack a wide range of color options. Slate can be found in green, purple, and red, but granite and marble make the most aesthetically pleasing headstones.

 

(Marble)

 

            To be long lasting, a material must resist weathering. Limestone contains calcite which is soluble in even slightly acidic water. As it rains, limestone is weathered away. The same is true of the somewhat more resilient marble. Granite also weathers, but at a much slower rate than marble. The feldspars in granite undergo hydrolysis to form clay and sodium and potassium ions which are eroded away and dissolved. Weathered granite is called grus. Sandstone is subject to weathering by frost wedging. Water gets into the small spaces between the sand grains and freezes, wedging the stone apart. Slate is nearly impermeable, but is thin and brittle, which makes it vulnerable to cracking.
 

(Slate)

 

            Some people opt for a simple shape with carved letters. Others want interesting shapes with intricate detail. If more complicated designs are an important factor, a softer stone is the right choice.  In geology hardness is a measure of how easily a material can be scratched. Carving sandstone can be dangerous. Sandstone produces a fine silica dust when carved and may cause silicosis if inhaled. Limestone is a good soft stone, but does not polish as well. Granite is the hardest of the common choices and requires special tools to be carved. The feldspars it contains are a level 6 on Mohís Scale of hardness and the quartz is a level 7. Slate can be very soft or as hard as granite. It has a wide range of hardness levels. Unless polish is important, limestone will produce the most ornate carvings. Marble, though slightly harder than limestone, is also a good choice for carving (just ask the ancient Greek masters!).

 

(Limestone)

 

            Limestone may carve easiest, but it weathers the fastest. Sandstone and slate are also prone to weather or fracture more rapidly. Marble is longer lasting, can be detailed to a degree and comes in hundreds of varieties, but granite best resists weathering and also provides many beautiful color options.

 

(Sandstone)

 

            Though not common, glass headstones have been dotting cemeteries in the 21st century. They are advertised to last thousands of years. Cast glass, is like a transparent, man-made quartzite in which the particles have been heated and frozen at random. Quartzite is a metamorphosed sandstone. It breaks into fragments across the individual grains unlike sandstone which breaks along the sand grains. Quartzite is an enduring material that is, unfortunately, unexciting and hard to work with. The natural version of glass, obsidian, is a black volcanic glass that is more susceptible to weathering. Man-made glass can be colored or frosted and crafted quite beautifully with the technology available today. That brings us to a final category in choosing a headstone: price and availability.

 

(Quartzite)

 

            Glass headstone prices start at 8,000 dollars and can run upward of 20,000 dollars depending on the design. Slate, limestone and sandstone monuments are very rare and extremely hard to find commercially. Regular marble gravestones start at 1,500 dollars. Marble statue memorials can be purchased from 3,000 dollars to 20,000 dollars. Single upright granite headstones start near 600 dollars. Double granite headstones can run up to 3,500 dollars.

 

Material

Color

Endurance

Hardness

Price

Glass

Any.

Longest lasting.

Hard.

$$$

Quartzite

Pale green to grey.

Long lasting.

Hard.

Unavailable.

Granite

Large variety

Long lasting.

Hard to moderate.

$

Marble

Large Variety

Fair.

Moderate.

$$

Sandstone

Grey, pale yellow, pink and red.

Easily weathered.

Dangerous to carve.

Unavailable.

Slate

Gray, green, purple and red.

Easily cracked or fractured.

Variable.

Unavailable.

Limestone

Grey, white, redish, and pale yellow.

Easily weathered.

Softest.

Unavailable.

 

           

           

           

           

 

 

 

 

 

 

 

 

(Table of materials)

 

            Overall, sandstone, slate and limestone fall short, lacking the longevity a memorial should have. Quartzite is hard to come by, and for good reason; it just isnít attractive. Granite is the most sensible choice. However, if price is not a factor, glass makes a lovely, surviving headstone. Marble can also prove to be a nice choice for those who like carved statues and symbols as opposed to laser etchings. All three are available, beautiful and have the longevity to honor the deceased. Choosing between them all depends on personal preference.

 

(Glass) Courtesy of Mayang Murni Adnin @ www.mayang.com/textures
 

Sites pertaining to headstone materials:

http://skywalker.cochise.edu/wellerr/aawellerweb.htm (This one!)

http://aboutstone.org/conversa/arc002/msg00302.html
http://www.stoneshaper.com/how.html#kind
http://geology.about.com/library/bl/images/blquartzite.htm
http://www.es.ucl.ac.uk/schools/Pancras/granite.htm
http://www.es.ucl.ac.uk/schools/Pancras/marble.htm
http://www.lundgrenmonuments.com/custom/customprojects.html