WARRANT AGENT AGREEMENT

Exhibit 4.1

WARRANT AGENT AGREEMENT

Dated as of January 28, 2005

by and among

OGLEBAY NORTON COMPANY

and

WELLS FARGO BANK, NATIONAL ASSOCIATION,

As Warrant Agent

WARRANT AGENT AGREEMENT

TABLE OF CONTENTS

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WARRANT AGENT AGREEMENT

WARRANT AGENT AGREEMENT dated as of January 28, 2005 (this “Warrant Agent Agreement”) between Oglebay Norton Company, an Ohio corporation, and Wells Fargo Bank, National Association, as warrant agent.

RECITALS

A. On February 23, 2004, ONCO Investment Company (“ONCO”) filed a voluntary petition for reorganization under Chapter 11 of Title 11 of the United States Code (the “Bankruptcy Code”) in the United States Bankruptcy Court for the District of Delaware (the “Bankruptcy Court”), which case is being jointly administered for procedural purposes before the Bankruptcy Court with the cases of the Company (as defined below) and all of the other direct and indirect wholly-owned subsidiaries of the Company (and collectively with ONCO, the “Debtors”) under case number 04-10558 (collectively, the “Chapter 11 Cases”).

B. Pursuant to the Second Amended Plan of Reorganization of Debtors and Debtors in Possession, dated July 30, 2004 (as further amended or modified, the “Plan”), which has been confirmed by the Bankruptcy Court in the Chapter 11 Cases, the Company is required to issue warrants (the “Warrants”) entitling the Holders (as defined below) to up to 576,256 shares of New Common Stock (as defined below).

C. The Company desires the Warrant Agent (as defined below) to act on behalf of the Company, and the Warrant Agent is willing to act as the agent of the Company in connection with the issuance, form, registration, exercise, transfer and exchange of the Warrants as well as other matters as provided herein.

NOW, THEREFORE, in consideration of the premises and the mutual covenants and agreements herein set forth, and for the purpose of defining the respective rights and obligations of the Company, the Warrant Agent and the Holders, the parties hereto agree as follows:

SECTION 1. Certain Definitions; General Interpretive Principles .

(a) Certain Definitions . As used in this Warrant Agent Agreement, the following terms will have the following respective meanings:

“Bankruptcy Code” has the meaning set forth in Recital A to this Warrant Agent Agreement.

“Bankruptcy Court” has the meaning set forth in Recital A to this Warrant Agent Agreement.

“Business Day” means any day, other than a Saturday or Sunday, on which national banking institutions in Cleveland, Ohio and Minneapolis, Minnesota are open.

“Chapter 11 Cases” has the meaning set forth in Recital A to this Warrant Agent Agreement.

“Company” means Oglebay Norton Company, an Ohio corporation, and its successors and assigns.

“Debtors” has the meaning set forth in Recital A to this Warrant Agent Agreement.

“Definitive Warrant Certificates” have the meaning set forth in Section 3.

“Definitive Warrants” have the meaning set forth in Section 3.

“Depositary” has the meaning set forth in Section 3.

“Distribution Record Date” means the date on which the Bankruptcy Court enters the order confirming the Plan pursuant to Section 1129 of the Bankruptcy Code.

“Distribution Record Date Stock Register” means the register listing each record holder of the Old Common Stock as of the close of business on the Distribution Record Date and setting forth the following information with respect to each such holder: (a) legal name, (b) mailing address, (c) tax identification number and (d) the number of shares of Old Common Stock registered with such record holder.

“Effective Date” means January 31, 2005.

“Exercise Amount” has the meaning set forth in Section 7(b).

“Exercise Price” means the purchase price per New Common Share to be paid upon the exercise of the Warrants in accordance with the terms hereof, which price will be $10.00 per New Common Share.

“Expiration Date” means March 2, 2005.

“Global Warrant Certificates” have the meaning set forth in Section 3.

“Global Warrants” have the meaning set forth in Section 3.

“Holder” means a person registered as the record holder of the Warrants.

“New Common Shares” means shares of New Common Stock.

“New Common Stock” means the common stock, par value $0.01 per share, of the Company on and after the Effective Date, and any other capital stock of the Company into which such common stock may be converted or reclassified or that may be issued in respect of, in exchange for, or in substitution for, such common stock by reason of any stock splits, stock dividends, distributions, mergers, consolidations or other like events.

“Officer” has the meaning set forth in Section 4.

“Old Common Stock” means the common stock, par value $1.00 per share, of the Company prior to the Effective Date.

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“Original Holder” means a person registered as the record holder of the Warrants on the Effective Date.

“ONCO” has the meaning set forth in Recital A to this Warrant Agent Agreement.

“Person” means any individual, corporation, partnership, joint venture, association, joint-stock company, trust, unincorporated organization or government or any agency or political subdivision thereof.

“Plan” has the meaning set forth in Recital B to this Warrant Agent Agreement.

“SEC” means the Securities and Exchange Commission.

“Securities Act” means the Securities Act of 1933, as amended.

“Transfer Agent” has the meaning set forth in Section 10.

“Warrant” or “Warrants” has the meaning set forth in Recital B to this Warrant Agent Agreement.

“Warrant Agent” means Wells Fargo Bank, National Association or the successor or successors of such Warrant Agent appointed in accordance with the terms hereof.

“Warrant Certificates” means the Definitive Warrant Certificates and the Global Warrant Certificates.

“Warrant Exercise Notice” has the meaning set forth in Section 7(b).

“Warrant Shares” means the New Common Shares issued or issuable upon the exercise of the Warrants.

(b) General Interpretative Principles . For purposes of this Warrant Agent Agreement, except as otherwise expressly provided or unless the context otherwise requires:

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SECTION 2. Appointment of Warrant Agent . The Company hereby appoints the Warrant Agent to act as agent for the Company in accordance with the instructions set forth hereinafter in this Warrant Agent Agreement, and the Warrant Agent hereby accepts such appointment, upon the terms and conditions hereinafter set forth.

SECTION 3. Form of Warrant Certificates . Subject to the provisions of this Warrant Agent Agreement, in accordance with the terms of the Plan, on the Effective Date, Warrants to purchase the Warrant Shares will be issued by the Company in the amounts and to the recipients specified in the Plan. The Warrants will be issued in definitive form (the “Definitive Warrants”), substantially in the form of Exhibit A-1, and in global form (the “Global Warrants”), substantially in the form of Exhibit A-2. Each certificate representing Global Warrants will represent such of the outstanding Warrants as will be specified therein and each certificate will provide that it will represent the aggregate amount of outstanding Warrants from time to time endorsed thereon and that the aggregate amount of outstanding Warrants represented thereby may from time to time be reduced or increased, as appropriate. The Depository Trust Company (the “Depositary”) will act as securities depositary for the Global Warrants. Upon request, a Holder may receive from the Depositary and the Warrant Agent separate Definitive Warrants as set forth in Section 6 below. Any certificates evidencing the Definitive Warrants (the “Definitive Warrant Certificates”) or the Global Warrants (the “Global Warrant Certificates”) to be delivered pursuant to this Warrant Agent Agreement will be substantially in the forms set forth in Exhibit A-1 and Exhibit A-2, respectively, attached hereto.

SECTION 4. Execution of Warrant Certificates . Warrant Certificates will be signed on behalf of the Company by its Chairman of the Board of Directors or its President and Chief Executive Officer or a Vice President and by its Secretary or an Assistant Secretary (each, an “Officer”). Each such signature upon the Warrant Certificates may be in the form of a facsimile signature of any present or any future Officer and may be imprinted or otherwise reproduced on the Warrant Certificates and for that purpose the Company may adopt and use the facsimile signature of any such Officer.

If any Officer who will have signed any of the Warrant Certificates will cease to be such Officer before the Warrant Certificates so signed will have been countersigned by the Warrant Agent, or disposed of by the Company, such Warrant Certificates nevertheless may be

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countersigned and delivered or disposed of as though such person had not ceased to be such Officer; and any Warrant Certificate may be signed on behalf of the Company by any person who, at the actual date of the execution of such Warrant Certificate, will be an Officer, although at the date of the execution of this Warrant Agent Agreement any such person was not such an Officer.

SECTION 5. Issuance of Warrants; Registration and Countersignature . The Warrant Agent, on behalf of the Company, will (a) number the Warrant Certificates received from the Company, (b) insert the name of the Holder and the number of Warrants and Warrant Shares such Holder is entitled to receive on each respective Warrant Certificate based on the information provided in the Distribution Record Date Stock Register to the Warrant Agent by the Company, and (c) register the Warrant Certificates in a register as they are issued.

The Warrant Agent will also countersign the Warrant Certificates. Warrant Certificates will be countersigned manually by the Warrant Agent and will not be valid for any purpose unless so countersigned. The Warrant Agent will, upon written instructions of the Chairman of the Board of Directors, the President and Chief Executive Officer or a Vice President of the Company, initially countersign, issue and deliver Warrants entitling the Holders thereof to purchase approximately the number of Warrant Shares referred to in Recital B above and will countersign and deliver Warrants as otherwise provided in this Warrant Agent Agreement.

On the Effective Date, the Warrant Agent will then arrange to deliver or cause to be delivered, by first class mail or overnight courier, the Warrant Certificates to the respective Holders at the mailing address set forth in the Distribution Record Date Stock Register.

The Company and the Warrant Agent may deem and treat the Holder(s) of the Warrant Certificates as the absolute owner(s) thereof (notwithstanding any notation of ownership or other writing thereon made by anyone), for all purposes, and neither the Company nor the Warrant Agent will be affected by any notice to the contrary.

SECTION 6. Registration of Transfers and Exchanges .

(a) Transfer and Exchange of Definitive Warrants . When Definitive Warrant Certificates are presented to the Warrant Agent with a written request:

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(b) Exchange of a Definitive Warrant for a Beneficial Interest in a Global Warrant . Upon receipt by the Warrant Agent of a Definitive Warrant that is not a restricted Warrant, duly endorsed or accompanied by appropriate instruments of transfer, in the form required by this Warrant Agent Agreement or satisfactory to the Warrant Agent, together with, written instructions directing the Warrant Agent to make, or to direct the Depositary to make, an endorsement on the Global Warrant Certificate to reflect an increase in the number of Warrants represented by the Global Warrant Certificate, then the Warrant Agent will cancel such Definitive Warrant and cause, or direct the Depositary to cause, in accordance with the standing instructions and procedures existing between the Depositary and the Warrant Agent, the number of Warrants represented by the Global Warrant Certificate to be increased accordingly. If no Global Warrant Certificate is then outstanding, the Company will issue and the Warrant Agent will countersign a new Global Warrant Certificate representing the appropriate number of Warrants.

(c) Transfer and Exchange of Global Warrants or Beneficial Interests Therein . The transfer and exchange of Global Warrants or beneficial interests represented by a Global Warrant Certificate will be effected through the Depositary, in accordance with this Warrant Agent Agreement and the procedures of the Depositary therefor.

(d) Exchange of a Beneficial Interest in a Global Warrant for a Definitive Warrant .

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(e) Restrictions on Transfer and Exchange of Global Warrants . Notwithstanding any other provisions of this Warrant Agent Agreement (other than the provisions set forth in Subsection (g) of this Section 6), a Global Warrant Certificate may not be transferred as a whole except by the Depositary to a nominee of the Depositary or by a nominee of the Depositary to the Depositary or another nominee of the Depositary or by the Depositary or any such nominee to a successor Depositary or a nominee of such successor Depositary.

(f) Countersigning of Definitive Warrants in Absence of Depositary. If at any time :

then the Company will execute, and the Warrant Agent, upon written instructions signed by two Officers of the Company, will countersign and deliver Definitive Warrant Certificates, in an aggregate number equal to the number of Warrants represented by Global Warrants, in exchange for such Global Warrants.

(g) Cancellation of Global Warrant . At such time as all beneficial interests in Global Warrants have either been exchanged for Definitive Warrants, exercised, redeemed, repurchased or cancelled, all Global Warrant Certificates will be returned to, and then cancelled by, the Warrant Agent.

(h) Obligations with respect to Transfers and Exchanges of Warrants .

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SECTION 7. Terms of Warrants; Exercise of Warrants . (a) Each Warrant will be exercisable at any time and from time to time beginning on the Effective Date and ending on 5:00 p.m., Eastern time, on the Expiration Date. After 5:00 p.m., Eastern time, on the Expiration Date, the Warrants will become void and of no value and all rights of the holder under the Warrant Certificate evidencing such Warrant and under this Warrant Agent Agreement will cease. On the Effective Date, each record holder of Old Common Stock as of the close of business on the Distribution Record Date will receive one Warrant for each share of Old Common Stock then held. Subject to the provisions of this Warrant Agent Agreement and applicable law, each Warrant issued on the Effective Date will entitle the Original Holder thereof to purchase from the Company (and the Company will issue and sell to such Original Holder) one-tenth (1/10th) of a fully paid and nonassessable share of New Common Stock. The Warrants will entitle the Holder thereof to purchase at the Exercise Price one Common Share for each ten (10) Warrants held. Except in the case where a Holder is exercising all Warrants then held, Warrant Shares may be purchased only pursuant to the exercise of Warrants in integral multiples of ten (10). No fractions of a Warrant Share will be issued upon exercise of any Warrants. If any fraction of a Warrant Share would be issuable on the exercise of all Warrants then held by a Holder, the number of Warrant Shares issuable to such Holder pursuant to such Warrants will reflect a rounding to the nearest whole number of Warrant Shares to be issued (up or down), with half shares being rounded up as provided in Section 11. The Warrants are transferable; provided, however, that any Warrants held by an affiliate of the Company may generally only be resold pursuant to a valid exemption under the Securities Act. The Warrants are exercisable by the subsequent Holder thereof pursuant to the terms and conditions provided in this Warrant Agent Agreement.

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(b) Warrants may be exercised upon surrender to the Company at the principal office of the Warrant Agent of (i) the certificate or certificates evidencing the Warrants to be exercised, (ii) the form of election to purchase on the reverse of such certificate or certificates (the “Warrant Exercise Notice”) duly filled in and signed, which signature must be guaranteed by an Eligible Guarantor Institution pursuant to SEC Rule 17Ad-15, and (iii) payment to the Warrant Agent, for the account of the Company, of the amount equal to the Exercise Price multiplied by the number of shares of New Common Stock (the “Exercise Amount”) of which such Warrants are then exercised. Payment of the Exercise Amount will be made to the Warrant Agent by certified check, official bank check, express money order, payable to the order of the Company, or by wire transfer in immediately available funds as follows:

Wells Fargo Bank, National Association

San Francisco, California

ABA # 121000248

A/C # 16749600

A/C Name: Oglebay Norton Company Warrants

REF: Wells Fargo Bank, National Association,

As Agent for Oglebay Norton Company

Attn: Jane Schweiger

The exercise of Warrants by Holders of beneficial interest in Global Warrants will be effected in accordance with this Warrant Agent Agreement and the procedures of the Depository therefor.

(c) All Warrant Certificates surrendered upon exercise of Warrants will be cancelled by the Warrant Agent. Such cancelled Warrant Certificates will then be disposed of by the Warrant Agent in accordance with the Warrant Agent’s customary procedures and shall provide evidence to the Company upon its request of any such cancelled Warrant Certificates. The Warrant Agent will account promptly to the Company with respect to Warrants exercised and concurrently pay to the Company all monies received by the Warrant Agent for the purchase of the Warrant Shares through the exercise of such Warrants. On or before the third day following the Expiration Date, the Warrant Agent will certify in writing, delivered as provided in Section 15 hereof, the actual number of Warrants exercised and paid for as of 5:00 p.m., Eastern time, on the Expiration Date.

(d) Any exercise of a Warrant pursuant to the terms of this Warrant Agent Agreement will be irrevocable and will constitute a binding agreement between the Holder and the Company, enforceable in accordance with its terms.

(e) The Warrant Agent will:

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(f) All questions as to the validity, form and sufficiency (including time of receipt) of a Warrant exercise will be determined by the Company in its sole discretion, which determination will be final and binding. The Warrant Agent will incur no liability for or in respect of such determination by the Company. The Company reserves the right to reject any and all Warrant Exercise Notices not in proper form or for which any corresponding agreement by the Company to exchange would, in the opinion of the Company, be unlawful. Such determination by the Company will be final and binding on the Holders, absent manifest error. Moreover, the Company reserves the absolute right to waive any of the conditions to the exercise of Warrants or defects in Warrant Exercise Notices with regard to any particular exercise of Warrants. The Company will be under no duty to give notice to the Holders of the Warrants of any irregularities in any exercise of Warrants, nor will it incur any liability for the failure to give such notice.

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(g) As soon as practicable after the exercise of any Warrant, the Company will issue, or otherwise deliver, in authorized denominations to or upon the order of the Holder of the Warrant Certificates evidencing such Warrants, either:

(h) The Warrant Agent will keep copies of this Warrant Agent Agreement and any notices given or received hereunder by or from the Company available for inspection by the Holders during normal business hours at its office. The Company will supply the Warrant Agent from time to time with such numbers of copies of this Warrant Agent Agreement as the Warrant Agent may request.

SECTION 8. Payment of Taxes . The Company will pay all documentary stamp taxes attributable to the initial issuance of Warrant Shares upon the exercise of Warrants; provided that the Company will not be required to pay any tax or taxes which may be payable in respect of any transfer involved in the issue of any new certificates evidencing the Warrants or any certificates for Warrant Shares in a name other than that of the registered Holder upon the exercise of Warrants, and the Company or the Warrant Agent will not be required to issue or deliver such new certificates evidencing the Warrants or certificates for Warrant Shares unless or until the person or persons requesting the issuance thereof will have paid to the Company the amount of such tax or will have established to the satisfaction of the Company that such tax has been paid.

SECTION 9. Mutilated or Missing Warrant Certificates . If any Warrant Certificate will be mutilated, lost, stolen or destroyed, the Company may in its discretion issue and the Warrant Agent may countersign in exchange and substitution for, and upon cancellation of, the Warrant

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Certificate, if mutilated or in lieu of and substitution for the Warrant Certificate, if lost, stolen or destroyed, a new certificate of like tenor evidencing an equal number of Warrants, but only upon receipt of evidence reasonably satisfactory to the Company and Warrant Agent of such loss, theft or destruction and indemnity and security therefor, if requested, also satisfactory to the Company and the Warrant Agent. Applicants for such substitute Warrant Certificate will also comply with such other reasonable regulations and pay such other reasonable charges as the Company or Warrant Agent may prescribe.

SECTION 10. Reservation of Warrant Shares . The Company will at all times reserve and keep available, free from preemptive rights, or any other actual contingent purchase rights of persons other than the Holders out of the aggregate of its authorized but unissued New Common Shares, for the purpose of enabling it to satisfy any obligation to issue Warrant Shares upon exercise of Warrants, the maximum number of New Common Shares which may then be deliverable upon the exercise of all outstanding Warrants.

The transfer agent for the New Common Stock (the “Transfer Agent”) and every subsequent transfer agent for any shares of the Company’s capital stock issuable upon the exercise of any of the rights of purchase aforesaid will be irrevocably authorized and directed at all times to reserve such number of authorized shares as will be required for such purpose. The Company will keep a copy of this Warrant Agent Agreement on file with the Transfer Agent and with every subsequent transfer agent for any shares of the Company’s capital stock issuable upon the exer