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                                                                    EXHIBIT 23.1

                       CONSENT OF INDEPENDENT ACCOUNTANTS

     We hereby consent to the use in this Registration Statement on Form S-1
(No. 333-95093) of our report dated November 5, 1999 relating to the financial
statements of Cabot Microelectronics Materials Division, a division of Cabot
Corporation, which appears in such Registration Statement. We also consent to
the references to us under the headings "Experts" and "Selected Financial Data"
in such Registration Statement.

                                            /s/ PRICEWATERHOUSECOOPERS LLP

Boston, Massachusetts
March 31, 2000