Ochre
Ochre (spelled Ocher in American engllsh) normally refers to a pigment associated with natural earth because it consists of a clay base which has a range of colours described as yellow ochre, red ochre, brown ochre, purple ochre, sienna ochre and umber ochre.
A yellow ochre, is yellow from the mineral goethite, an iron oxide hydroxide (limonite). Red ochre, takes its red colour from the mineral hematite, which is an anhydrous iron oxide. Brown ochre, takes its colour from goethite, a partly hydrated iron oxide. Whilst sienna and umber ochres take their colours from differing amounts of manganese oxide.
The use of red ochre pigments have been dated by archaeologists as early as 300,000 years ago, around the time of the emergence of Homo sapiens. The use
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
Construction Management, 2 June
Construction deaths halve in two years.
Green Book changes to drive investment in all parts of UK.
Minimum energy efficiency standards (MEES)
CIAT briefing on response to consultations for privately rented non-domestic properties.
Connect, collaborate, shape the future
Registration now live for UK Construction Week Birmingham.
CIOB announces Saul Humphrey FCIOB as new President for 26/27 term.
A quick, simple, and zero-bills solution to prevent overheating.
The adaptive reuse of large industrial structures.
Promoting the circular economy by extending the life of buildings.
CIAT responds to Climate Change Committee report
An urgent wake-up call for both government and the built environment.
Construction Management, 24 June
FMB pilot aims to build pipeline of site-ready tradespeople.
A quick introduction.
CLC publishes Mental Health Joint Code of Practice.
A quick introduction to its uses and risks.