Macaulayite
A variety of Minerals
What is Macaulayite?
Macaulayite is a red, earthy, monoclinic mineral, with the chemical formula (Fe, Al)24Si4O43(OH)2. It was discovered in the 1970s by Dr Jeff Wilson and named after the Macaulay Institute in Aberdeen, Scotland. The only known source of macaulayite in the world is a quarry at the foot of Bennachie, Aberdeenshire, and it is formed by granite which has been weathered by tropical climates from before the last Ice Age. The substance is currently being studied by NASA, as it is speculated that this is the substance which gives the planet Mars its colour and it could prove that life on Mars can be sustained.
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Macaulayite before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Macaulayite Localities Map
See where Macaulayite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Quick Facts
Physical Properties
- Color
- Red
- Density
- 4.41 g/cm³
Chemical Properties
- Chemical Formula
- (Fe,Al)24Si4O43(OH)2 In the type material, Fe:Al is approximately 13:1.
- Elements
- Al, Fe, H, O, Si
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Macaulayite FAQs
How do I identify Macaulayite?
Macaulayite can be identified by its Red color. Look for these key characteristics when examining specimens.
What color is Macaulayite?
Macaulayite typically appears in Red. Color can vary depending on impurities and formation conditions.
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