Project Attributes
Global project


Project Clock





University of Sydney


Concept Partners



Gravestone Title

Welcome to the global Gravestone Project. This project aims to map the location of a graveyards around the globe and then use marble gravestones in those graveyards to measure the weathering rate of marble at that location.

We have been collecting data for over a year....but really need your help to collect more data. Click here to read the report for the first year.

(Please note that as this project involved visiting areas considered to be sacred to many people, taking school or other student groups to work on this project is not advised.)

Introduction video (English)


The weathering rates of gravestones are an indication of changes in the acidity of rainfall between locations and over time. The acidity is affected by air pollution and other factors, and could be used as a measure of changes in climate and pollution levels.

This project has two levels of data collection. The Graveyard Data level - the location of graveyards - requires only a GPS. The Gravestone Data level - the measurement of the weathering of marble gravestones - requires a micrometer. You can do the first or both tasks, but strongly suggest that before you purchase a micrometer (available through the EarthTrek online store, at hardware and some hobby stores) that you make sure that you can locate the type of gravestone.

Collecting the location data of the graveyards is an important part of this project. Logging data about graveyards that do not contain the marble gravestones is equally important.

Read the report from the first year of data collecting (click here).

Earn a free Gravestone Project pin for participating. (...more)

Project Background
Every time it rains the raindrops contain more than just water. As well as the small particles of dust that the water drops formed around, the water can contain chemicals found in the atmosphere. Often the rain will end up being slightly acidic. This ‘acid’ rain can then chemically affect (weather) materials in which it comes in contact. The amount of weathering that occurs from place to place differs and may be changing over time.

Marble is a common stone used to make gravestones. Marble is mostly made up of the mineral calcite. Calcite is a carbonate mineral, and so it reacts with any acid, including the weak rainfall acids, and dissolves. This means that over time, marble headstones are slowly weathering away.

This project aims to measure how fast the marble gravestones in graveyards you visit are weathering and see how that may be changing over time. This could be an indicator of changes in pollution or climate.

There are two method you can use in this project to measure the weathering rate in marble gravestones.

Lead lettering method
One method to measure the rates of this weathering is to use a certain type of gravestone (marble) that has lead lettering. When these gravestones are created, letters are carved into the stone and then lead is gently tapped into the letters. The stonemason then polishes the gravestone smooth so that the lead letters and the surface of the marble are flush (exactly the same height).

Marble-Lead gravestone

A Marble-Lead gravestone in Sydney, Australia.

The raw stone, marble, is made up of minerals that are carbonates (mostly calcium carbonate) which is affected by acidic rain. The lead in the lettering is, by comparison, not affected by the acid rain. Over time and exposure to the acidic rain, the marble weathers and erodes while the lead does not. So eventually the lead lettering appears to stand up from the surface of the marble.

Lead higher than marble

Lead standing up higher than the marble

By measuring the distance from the top of the lead letters to the weathered marble, and recording the date of the gravestone, we can work out a weathering rate over time of the marble. Because we can find gravestones of different ages, we can also work out if the rate has changed over time.

Gravestones that are made of marble and contain lead lettering are called Marble-Lead gravestones in this study.

Thickness method
The second method can be used for marble gravestones that do not contain lead lettering. It assumes that when the headstone was made it was cut and polished so that it was a constant thickness.

Marble gravestone

A marble gravestone with no lead lettering - Arlington Cemetery, Washington DC, USA

By measuring the thickness of the same headstone at the bottom and top, you can determine if there has been a change in the thickness over time. While not as accurate as the lead lettering method, it can be used as a way to determine weathering in locations where lead lettering was not used.

Measuring marble

Measuring the middle thickness of a marble gravestone

In some places, both methods can be used to tie the results of both methods together for scientific accuracy.

What do I need to do?

To participate in this project you will need to:

Graveyard Data level (requires only a GPS)(….more)

1. Learn to identify the marble gravestones - both with and without lead lettering.

2. Visit graveyards and find marble gravestones.

3. Record information for the graveyard data on the project data sheet.

Gravestone Data level (requires a GPS, calipers and a small tape measure)(….more)

1. Locate five gravestones

2. Collect five measurements at each gravestone

3. Record information gathered from the gravestones on the project data sheet.

Log your data

Complete the online form from these pages using the data you have collected at the graveyards