Portlandite
| Portlandite | ||
|---|---|---|
Specific gravity 2.23 | | |
| Optical properties | Uniaxial (−) | |
| Refractive index | nω = 1.574 nε = 1.547 | |
| Birefringence | δ = 0.027 | |
| Solubility | Soluble in water producing an alkaline solution | |
| Alters to | Alters to CaCO3 on exposure to CO2 bearing waters | |
| References | [2][3][4][5][6] | |
Portlandite is a hydroxide-bearing mineral typically included in the oxide mineral class. It is the naturally occurring form of calcium hydroxide (Ca(OH)2) and the calcium analogue of brucite (Mg(OH)2).
Occurrence
Portlandite occurs in a variety of environments. At the
Negev desert in Israel and the Maqarin area, Jordan.[3] It also occurs in the manganese mining area of Kuruman, Cape Province, South Africa in the Kalahari Desert where it occurs as large crystals and masses.[4][3]
It occurs in association with
mayenite and ettringite.[3]
It was first described in 1933 for an occurrence at Scawt Hill, Larne, County Antrim, Northern Ireland. It was named portlandite because the chemical calcium hydroxide is a common hydrolysis product of Portland cement.[4][3]
References
- S2CID 235729616.
- ^ "Mineralienatlas - Fossilienatlas". www.mineralienatlas.de.
- ^ a b c d e "Handbook of Mineralogy" (PDF).
- ^ a b c "Portlandite: Mineral information, data and localities". www.mindat.org.
- ^ "Portlandite Mineral Data". www.webmineral.com.
- ISBN 9780471192398.