FAQ

Frequently Asked Questions on Sulfur-Species Problems

The following page answers some of the frequently asked questions related to pyrite, pyrite-heave, gypsum, sulfate attack and a wide variety of other aspects related to the engineering implications of pyrite and other sulfur-species. This page is a work-in-progress and is updated regularly. If you have a question, please use the Contact page to get in touch.

Note

PyriteProblem.com is not responsible for information provided on external websites that may be linked to in the below text. The information contained on this website, and those of external websites may be (or become) inaccurate.

Pyrite

Q. What is pyrite? (similarly: what is fool’s gold?)

A. Pyrite is an iron sulfide mineral (FeS2) which oxidises on exposure to oxygen and water.

Q. What is the colour of pyrite? (similarly: what is the appearance of pyrite?)

A. Pyrite has a metallic ‘lustre’ and a brassy-yellow hue. This is the reason for the nickname of ‘fool’s gold’.

Q. Is pyrite a metal?

A. Pyrite is an iron sulfide mineral, not a metal, but is commonly associated with metals such as nickel, iron and gold in rocks.

Q. Is pyrite magnetic?

A. Pyrite is non-magnetic.

Q. What is/was pyrite used for? (similarly: what are the uses of pyrite?)

A. PyriteProblem.com has a detailed list of historic and modern uses of pyrite – please click here to find out more.

Q. What problems does pyrite cause when present in roofing slates?

A. The oxidation of pyrite may lead to red-brown spots of iron-oxides (rust) on decorative stone and some building materials, such as slates. This process largely results in unattractive materials, however in certain cases, the materials can become weakened and defective. For more information about the nature of pyrite in roofing slates, please click here.

 

Pyrite-induced heave

Q. What is “heave”

A. Heave is defined in different ways, but typically refers to the movement or displacement of an object. With respect to pyrite damage, the phrases “sulfate heave”, “sulfate-generated heave” and most commonly “pyrite heave” or “pyrite-induced heave” are all used to describe firstly the expansion of pyritic aggregates due to the growth of sulfate minerals and secondly the effect of this process on structures (typically vertical upward movement resulting in cracking and rising of house floor slabs).

Q. Where can I find information on the pyrite problems in Ireland? (similarly: what is the history of pyrite problems in Ireland?)

A. PyriteProblem.com has a detailed historical summary of the Irish pyrite problems. Please click here to read it.

Q. Where can I find resources related to the pyrite problems in Ireland? (similarly: where can I find technical documents, guidance for homeowners etc regarding pyrite problems in Ireland?)

A. PyriteProblem.com has a list of resources related to the Irish pyrite problems. Please click here to read it.

Q. I think my property is suffering from damage due to pyrite heave – what should I do?

A. This depends on your location. Typically, sampling and testing of the sub-floor aggregate is the first stage in order to assess the chemistry of the aggregate and determine whether pyrite or its oxidation products are present.

Q. I have concerns about the effects of pyrite damage on a domestic gas installation – what should I do?

A. Gas Networks Ireland provides guidance on this topic. Please click here to view their website.

Q. I have concerns that pyrite may be present in the backfill around the drainage, pathways and driveways of my property – what should I do?

A. Heave of pyritic aggregates used to backfill services and pathways etc. could result in the movement of pipes and/or overlying paving slabs as well as cracking to driveways. Typically, sampling and testing of sub-floor aggregate is the first stage in order to assess the chemistry of the aggregate and determine whether pyrite or its oxidation products are present.

Q. Where can I find information on legal cases concerning pyrite problems in Ireland?

A. PyriteProblem.com has a number of posts relating to legal cases. Click here to read more about the James Elliott v Irish Asphalt case.

Gypsum

Q. What are the typical appearances of gypsum crystals in soils?

A. Gypsum exhibits a wide range of mineralogical features when present as coarse crystals, sometimes known as selenite. PyriteProblem.com has a post on the mineralogy of gypsum crystals – click here to read it, as well as the nature of gypsum nodules – click here to read it.

More coming soon, including the below – please check back.

Q. What is framboidal pyrite?

Q. How is pyrite formed?

Q. Where is pyrite found? (similarly: what types of rock is pyrite found in?)

Q. What are the properties of pyrite?

Q. What are the typical signs of pyrite damage?

Q. How quickly does pyrite heave and the associated damage occur?

Q. Will the pyrite damage eventually stop? If so, when?

Q. How is pyrite heave remediated? (similarly: what is the solution to the pyrite problem?)

Q. Are there any short-term measures I can take to slow-down the damage process

Q. What is Delayed Ettringite Formation (DEF)?

Q. What is Internal Sulfate Attack (ISA)?

Q. What is the thaumasite form of sulfate attack?

Q. What is Total Potential Sulfate (TPS)?

Q. What is Acid Soluble Sulfate?

Q. What is Water Soluble Sulfate?

Q. What is the “BRE Suite” of chemical testing of soils/rocks?

Q. What are the environmental and engineering implications of pyrite oxidation?

Q. What is pyrrhotite?

Q. What are the environmental and engineering implications of pyrrhotite oxidation?

Q. What is the Pyrite Resolution Board? Where can I find updates on their progress?