Princeton, New Jersey; November 30, 2006 — Rockwood Holdings, Inc. (NYSE: ROC), a global producer of specialty chemicals and advanced materials, today announced that it has signed a definitive agreement to sell its Groupe Novasep subsidiary to a consortium of buyers comprising Gilde Buyout Partners BV, Banexi Capital and Groupe Novasep management. This transaction values Groupe Novasep at approximately €425 million.

Gilde Buyout Partners is a private equity investor operating out of Utrecht (NL), Zurich (SW) and Paris. Groupe Novasep is a technology-driven company serving the life sciences and specialty chemical industries. The company specializes in production of active pharmaceutical ingredients, developing new purification processes and large-scale chromatography. Groupe Novasep is 78.6 percent owned by Rockwood Holdings. The remainder is owned by Groupe Novasep management.

The transaction is subject to limited conditions, including competition clearance in the European Union and United States. Rockwood expects the transaction to close within 60 days.

JPMorgan, Cazenove and Lazard acted as financial advisors to Rockwood on this transaction.