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Exhibit 4.6

        EXECUTION COPY

SUPPLEMENTAL INDENTURE (this "Supplemental Indenture") dated as of July 31, 2004, by and among CERAMTEC NORTH AMERICA INNOVATIVE CERAMIC ENGINEERING CORPORATION, CHEMETALL CHEMICAL PRODUCTS INC., CHEMETALL CORPORATION, CHEMETALL XXXXX CORP., XXXXX CHILE HOLDING COMPANY, OAKITE PRODUCTS, INC. AND XXXXXXXXXX CORPORATION (each, a "New Guarantor" and collectively, the "New Guarantors"), each, an indirect subsidiary of ROCKWOOD SPECIALTIES GROUP, INC., a Delaware corporation (the "Company" or the "Issuer"), the Company and THE BANK OF NEW YORK, a New York banking corporation, as trustee under the Indenture referred to below (the "Trustee").

WITNESSETH:

        WHEREAS the Company and the Guarantors named in the Indenture (as defined) have heretofore executed and delivered to the Trustee an Indenture (the "Indenture") dated as of July 23, 2003, providing for the issuance of an aggregate principal amount of $375,000,000 of 10⁵/8% Senior Subordinated Notes due 2011 (the "Notes");

        WHEREAS the New Guarantors are guaranteeing certain other indebtedness of the Company as of the date hereof;

        WHEREAS Section 1015 and Section 1203 of the Indenture provide that the Company shall cause the New Guarantors to execute and deliver to the Trustee a supplemental indenture in accordance with the provisions of clause (10) of Section 901 of the Indenture pursuant to which the New Guarantors shall guarantee all of the Company's Obligations under the Notes; and

        WHEREAS pursuant to Section 1015 and Section 1203 of the Indenture, the Trustee, the Company and the New Guarantors are authorized to execute and deliver this Supplemental Indenture;

        NOW THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the New Guarantors, the Company and the Trustee mutually covenant and agree for the equal and ratable benefit of the holders of the Notes as follows:

        1.    Agreement to Guarantee.    Subject to the provisions hereof, each New Guarantor hereby agrees, jointly and severally with all existing Guarantors, to unconditionally and irrevocably guarantee, on an unsecured senior subordinated basis, the Company's obligations under the Notes on the terms, and subject to the conditions of, Article Twelve of the Indenture and to be bound by all other applicable provisions of the Indenture and the Notes.

        2.    Ratification of Indenture; Supplemental Indenture Part of Indenture.    Except as expressly amended hereby, the Indenture is in all respects ratified and confirmed and all the terms, conditions and provisions thereof shall remain in full force and effect. This Supplemental Indenture shall form a part of the Indenture for all purposes, and every holder of Notes heretofore or hereafter authenticated and delivered shall be bound hereby.

        3.    Governing Law.    THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

        4.    Trustee Makes No Representation.    The Trustee makes no representation as to be validity or sufficiency of this Supplemental Indenture. The recitals and statements herein are deemed to be those of the Company and the New Guarantors and not of the Trustee.

        5.    Counterparts.    The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement.

        6.    Effect of headings.    The Section headings herein are for convenience only and shall not effect the construction thereof.

        [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

        IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed as of the date first above written.

		CERAMTEC NORTH AMERICA INNOVATIVE CERAMIC ENGINEERING CORPORATION
		By:		/s/  XXXXXX XXXXXXX
				Name: Xxxxxx Xxxxxxx
				Title: President/CEO
		CHEMETALL CHEMICAL PRODUCTS INC.
		By:		/s/  XXXXXX X. XXXXX
				Name: Xxxxxx X. Xxxxx
				Title: President
		CHEMETALL CORPORATION
		By:		/s/  XXXXXX X. XXXXX
				Name: Xxxxxx X. Xxxxx
				Title: Vice President
		CHEMETALL XXXXX CORP.
		By:		/s/  XXXX X. XXXXXX
				Name: Xxxx X. Xxxxxx
				Title: Vice President
		XXXXX CHILE HOLDING COMPANY
		By:		/s/  XXXX X. XXXXXX
				Name: Xxxx X. Xxxxxx
				Title: Vice President
		OAKITE PRODUCTS, INC.
		By:		/s/  XXXXXXX X. XXXX
				Name: Xxxxxxx X. Xxxx
				Title: Secretary
		XXXXXXXXXX CORPORATION
		By:		/s/  XXXX XXXXXXX
				Name: Xxxx Xxxxxxx
				Title: Vice President Plastics and Coatings            Market
		ROCKWOOD SPECIALTIES GROUP, INC., as Issuer
		By:		/s/  XXXXXXX X. XXXXXXX
				Name: Xxxxxxx X. Xxxxxxx
				Title: Assistant Secretary
		THE BANK OF NEW YORK, as Trustee
		By:		/s/  XXXXXXX XXXXXX
				Name: Xxxxxxx Xxxxxx
				Title: Vice President

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Exhibit 4.6
WITNESSETH