
Maria Lóbez: Brooch, L'invisible 1 2008
Silver, methacrylate (via Klimt02)

Marielle Ledoux: Brooch, Untitled 2008
Rubber (via Klimt02)

Célio Braga: Brooch, Untitled 2007 (via Klimt02)
Textile, felt, glass, hair
Looks like it's covered in Boulangerite crystals.

Yu-Chun Chen: Brooch, Flowerness of the bird II 2007
Iron, paint, horn, steel (via Klimt02)

Flora Vagi: Necklace, Untitled 2007
Wood, silk (via Klimt02)
Update: I thought I should include some real minerals too...
Ferberite from Bolivia via Mineral Classics
Ferberite (rare doubley terminated twin) on matrix from Bolivia via Mineral Classics