Otwayite, Ni2CO3(OH)2, is a hydrated nickel carbonate mineral. It is a green orthorhombic hydrated nickel carbonate mineral. It is green, with a hardness of 4, a specific gravity of 3.4, and crystallizes in the orthorhombic system. It is found in the Nullagine region of Western Australia, and occurs as fibrous veinlets in a nickel-rich assemblage. It is a mineral closely related to paraotwayite.
It was named in 1977 by Ernest H. Nickel, Bruce W. Robinson, Charles E.S. Davis in honor of Mr. Charles Albert Otway (b. 1922) of Gosnells (Perth), Western Australia, a prospector and miner who held the mineral lease and provided samples of the mineral.
- Category: Carbonate mineral
- Formula: (repeating unit) Ni2CO3(OH)2
- Crystal system: Orthorhombic
- Color: Bright green
- Specific Gravity: 3.41
Otwayite is green, with a hardness of 4, a specific gravity of 3.4, and crystallizes in the orthorhombic system. It is found in association with theoprastite, hellyerite, gaspeite, and a suite of other nickel carbonate minerals in the Lord Brassey Mine, Tasmania.
- Crystal habit: Sprays of Fibrous bundles oriented perpendicular to veinlet walls; spherules and claylike coatings
- Mohs scale hardness: 4
- Luster: Silky to waxy
- Diaphaneity: Opaque to translucent
- Specific gravity: 3.41
- Optical properties: Biaxial
Occurrence – In veinlets in serpentinite (Otway prospect, Western Australia; Lord Brassey mine, Tasmania, Australia).
In the Otway nickel deposit, otwayite is found in association with nullaginite and hellyerite. It is found in Tasmania’s Lord Brassey Mine with theoprastite, hellyerite, gaspeite, and a variety of other nickel carbonate minerals.
In the Widgie Townsite nickel gossan, Widgiemooltha, Western Australia, otwayite is found in association with gaspeite, hellyerite, and kambaldaite. It has also been reported from South Africa’s Pafuri nickel deposit. It was named after Australian prospector Charles Albert Otway and was first described in 1977 from the Otway Nickel Deposit, Nullagine, Pilbara Craton, Western Australia (born 1922).
Association: Magnesite, pecoraite, gasp´eite, paraotwayite, millerite, polydymite, nickeloan chrysotile, apatite (Otway deposit, Western Australia); theophrastite, hellyerite, zaratite, magnetite (Lord Brassey mine, Tasmania, Australia).