Mineralpedia Details for Willemite
The first, and self-proclaimed, King of the Netherlands, William I, has the honor of Willemite being named for him. At the time, the type locality of Willemite was in the Netherlands. Willemite is a secondary mineral, usually in limestone-developed zinc deposits. An uncommon but important ore of zinc at some of its many widespread localities. Willemite is highly fluorescent as a yellow-green to –orange under both short-wave and long-wave ultraviolet light and may also be phosphorescent.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/willemite.pdf
- Crystal System
- Crystal Habit
- Prismatic, Massive - Granular, Massive
- Poor, Poor, None
- Vitreous - Resinous
- white, yellow, green, reddish brown, black
- Trigonal - Rhombohedral
- View Willemite
- View Willemite
Willemite from Grootfontein, Namibia
Clear, prismatic crystals to 3mm in exceptional sprays.
Willemite from Sterling Hill mine, Ogdensburg, Sussex Co., New Jersey, United States
A large well formed Willemite crystal to 2cm perched on a bit of Calcite-Willemite-Franklinite matrix.
Willemite from Tsumeb mine, Tsumeb, Namibia
Light mint green Willemite crystals to 3mm as singles and groups with yellow Mimetite. Notice the light green balls are Malachite.
Reddish brown "Trootsite" a mangansese rich variety of Willemite, which also occurs at Franklin. The Tsumeb trootsite is botryoidal however and composed of aggregates of rich reddish brown curved and balled up rhombic crystals.
Willemite from Franklin, Sussex Co., New Jersey, United States
Excellent prismatic, striated, and clear WIllemite crystals to about 1.5mm with other thicker and larger in a seam lined with orange, pseudorhombohedral crystals to about 0.75mm.
Lime green crystalline Willemite. Acquired by Hampson in 1945. Intense green fluorescence.
Willemite from Lusaka, Lusaka Province, Zambia
- Special Info
Colorless, acicular Willemite, which is intensely fluorescent green in open cavities with radial compact, brown crystals in the matrix. The matrix does not fluoresce, indicating it is not Willemite.