Superb Norway Designer Unn Tangerud for David Andersen Sterling & Thulite Retro Modernist Convertible Brooch Necklace From the 1960s Trolls Series

Measurements: 2.1"L x 2.1"W x .4"Thick (5.33cm x 5.33cm x 1.02cm) 

Chain: 19"L (48.26cm)

Markings: UNI D-A - 925S - Sterling - Norway - Inv.U.T.

Weight: 27.3g

Superb modernist sterling and Amazonite brooch/pendant necklace. It has been professionally polished and is in excellent condition. Stone is fully intact with no damage and is shiny and bright. Any weird black lines or marks in the photos are just reflections or shadows. It's very shiny and hard to photograph. 

Mannequin is a life-size torso representation

The jewelry of Unn Tangerud has an expression of simplistic primitive sophistication, often inspired by an ancient Nordic culture. Her materials are silver, bronze or copper with semi-precious stones or enamel. She originally trained as a ceramicist at The Norwegian Arts and Crafts School (SHKS) in Oslo, graduating in 1956.
In 1959, Uni David-Andersen, the great granddaughter of the founder of the David-Andersen company in Oslo, started up a small workshop of her own. Together with female designers such as Unn Tangerud and Marianne Berg, Uni experimented 
with new technics and free sculptural styles for jewelry production. The results were both unique pieces, as well as models for larger scale production at David-Andersen.
The two “Troll series”
When in 1964 David-Andersen launched a new collection of cast silver jewelry called the Troll Series, one of the more popular pieces was a brooch named ‘Unn’s Sun Chariot’, designed by Unn Tangerud. This collection of cast jewelry is characterized by a new sense of simplicity, and the use of stones found in Norway, such as Amazonite and Thulite. A prominent point in the creation of this collection was the increased emphasis on the artistic value of the pieces themselves, rather than on the economic value of the materials used.
Later works
Working onwards from the Troll Series, Unn Tangerud has created her designs using repetitions of a motif as a means of expressing her idea. This is found in both her bronze and her silver jewelry, where elements of metal are put together on various patterns. In this work is a possible parallel to her Finnish colleague Pentti Sarpaneva recognizable. Amongst her later works are found enameled pieces in a series called Rustika,

where generous shapes inspired by the forms and sensations of the Jugend/Art Noveau period merge with the brighter language of color found in the innovative enamel works of the seventies. 

The company was founded in Christiania (now Oslo), Norway by David Andersen in 1876. Andersen (1843-1901) was a gold and silversmith with a keen sense of quality and the high standards of his workmanship brought early success to the firm. By 1888, Andersen was able to expand his workshop into a steam powered plant and a second retail location was opened in Oslo in 1892.
David Andersen died in 1901, his son, Arthur Andersen, took the reins of the firm at that time. Arthur instituted some important changes, he decided to hyphenate the family name to David-Andersen, and as chief designer, he introduced the use of enameling on the company's gold and silver jewelry as well as hollowware. The new line was so successful that enamelled jewelry has become nearly synonymous with the David-Andersen name. The firm has remained a family business and is now run by members of the fourth generation, Uni and Jon David-Andersen.