<PAGE>   1
                                                                   EXHIBIT 4.12


[UNLESS THIS SECURITY IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE CORPORATION
(AS DEFINED BELOW) OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR
PAYMENT, AND ANY SECURITY ISSUED IS REGISTERED IN THE NAME OF CEDE & CO., OR
SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED
OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

         TRANSFERS OF THIS SECURITY SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT
NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR SUCH SUCCESSOR'S
NOMINEE AND TRANSFERS OF PORTIONS OF THIS SECURITY SHALL BE LIMITED TO
TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN SECTION 2.9 OF
THE INDENTURE (AS DEFINED BELOW).]*

---------

* Include only on a Global Note.


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No.                                                            $
   ---------                                                    ---------------

                        MARTIN MARIETTA MATERIALS, INC.

                                     6.875%

                             Note Due April 1, 2011

                                                                CUSIP 573284AG1

MARTIN MARIETTA MATERIALS, INC., a North Carolina corporation, for value
received hereby promises to pay to Cede & Co., or registered assigns, the
principal sum of _______________________________________________
($________________) on April 1, 2011.



         Interest Payment Dates:            April 1 and October 1, commencing
                                            October 1, 2001

         Record Dates:                      March 15 and September 15

Additional Provisions of this Note are set forth on the following pages of this
Note.

Attest:           [SEAL]                    MARTIN MARIETTA MATERIALS, INC.



                                            By:
---------------------------------              --------------------------------
Secretary                                      Chief Executive Officer

Dated:

Authenticated:

This is one of the Securities of
the series designated herein and
referred to in the within-named
Indenture.

FIRST UNION NATIONAL BANK,
    as Trustee



By:
   ------------------------------
   Authorized Officer


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                        MARTIN MARIETTA MATERIALS, INC.

                                     6.875%

                             NOTE DUE APRIL 1, 2011

         1.       Interest. Martin Marietta Materials, Inc., a North Carolina
corporation (the "Corporation"), promises to pay interest on the principal
amount of this Security at the rate per annum shown above. The Corporation will
pay interest semi-annually on April 1 and October 1 of each year, commencing on
October 1, 2001. Interest on the Securities will accrue from the most recent
date to which interest has been paid, or if no interest has been paid, from
March 30, 2001. Unless otherwise specified, interest will be computed on the
basis of a 360-day year of twelve 30-day months.

         2.       Method of Payment. Except as described above, the Corporation
will pay interest on the Securities of this series (except defaulted interest,
which shall be paid as set forth below) to the persons who are registered
holders of the Securities at the close of business on the record date for the
next interest payment date even though the Securities are cancelled after the
record date and on or before the interest payment date. Any such interest not
so punctually paid or duly provided for will forthwith cease to be payable to
the Holder on such regular record date and may either be paid to the Person in
whose name this Security (or one or more predecessor Securities) is registered
at the close of business on a special record date for the payment of such
defaulted interest to be fixed by the Trustee for the Securities, notice
whereof shall be given to the Holders of Securities not less than 15 days prior
to such special record date, or may be paid at any time in any other lawful
manner not inconsistent with the requirements of any securities exchange on
which this Security may be listed, and upon such notice as may be required by
such exchange, all as more fully provided in the Indenture. Holders must
surrender the Securities to a Paying Agent to collect principal payments. The
Corporation will pay principal and interest in the money of the United States
that at the time of payment is legal tender for payment of public and private
debts. However, the Corporation may pay principal and interest on Securities
(other than Global Securities) by its check payable in such money. It may mail
any such interest check to a holder's registered address. All payments of
principal and interest with respect to the Global Securities will be made by
the Corporation in immediately available funds. To the extent lawful, the
Corporation shall pay interest on overdue principal at the rate borne by the
Securities and it shall pay interest on overdue installments of interest at the
same rate.

         3.       Paying Agent and Registrar. Initially, First Union National
Bank ("Trustee"), Corporate Trust Division, 401 South Tryon Street, 12th Floor,
Charlotte, North Carolina 28288-1179, will act as Paying Agent and Registrar.
The Corporation may change any Paying Agent, Registrar or co-registrar without
notice. The Corporation or any of its Subsidiaries (as defined in the
Indenture) may act as Paying Agent, Registrar or co-registrar.

         4.       Indenture. The Corporation issued the Securities under an
Indenture dated as of December 7, 1998 ("Indenture"), between the Corporation
and the Trustee, as supplemented by the resolutions of the Corporation dated
March 27, 2001. The terms of the Securities include those stated in the
Indenture and those made part of the Indenture by reference to the Trust
Indenture Act of 1939 (15 U.S. Code ss.ss. 77aaa-77bbbb) ("Act"). The
Securities are subject to


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all such terms, and holders are referred to the Indenture, all applicable
supplemental indentures and the Act for a statement of those terms. As provided
in the Indenture, the Securities may be issued in one or more series, which
different series may be issued in various aggregate principal amounts, may
mature at different times, may bear interest, if any, at different rates, may
be subject to different redemption provisions, if any, may be subject to
different sinking purchase or analogous funds, if any, may be subject to
different covenants and Events of Default and may otherwise vary as in the
Indenture provided or permitted. This Security is one of a series of the
Securities designated on the face hereof, limited in aggregate principal amount
of $250,000,000 (except as otherwise provided in the Indenture).

         5.       Redemption. The Securities of this series will be redeemable
at the option of the Corporation, in whole at any time or in part from time to
time, on at least 30 days but not more than 60 days prior written notice mailed
to the registered holders thereof, at a redemption price equal to the greater
of (i) 100% of the principal amount of the Securities of this series to be
redeemed or (ii) the sum, as determined by the Quotation Agent (as defined
herein), of the present values of the principal amount of the Securities to be
redeemed and the remaining scheduled payments of interest thereon from the
redemption date to the maturity date of the Securities to be redeemed,
exclusive of interest accrued to the redemption date (the "Remaining Life"),
discounted from their respective scheduled payment dates to the redemption date
on a semiannual basis (assuming a 360-day year consisting of 30-day months) at
the Treasury Rate (as defined herein) plus 25 basis points plus accrued and
unpaid interest on the principal amount being redeemed to the date of
redemption.

         If money sufficient to pay the redemption price of and accrued
interest on all the Securities (or portions thereof) to be redeemed on the
redemption date is deposited with the Trustee or paying agent on or before the
redemption date and certain other conditions are satisfied, then on and after
such redemption date, interest will cease to accrue on such Securities (or such
portion thereof) called for redemption.

         "Comparable Treasury Issue" means the United States Treasury security
selected by the Quotation Agent as having a maturity comparable to the
Remaining Life that would be utilized, at the time of selection and in
accordance with customary financial practice, in pricing new issues of
corporate debt securities of comparable maturity with the Remaining Life.

         "Comparable Treasury Price" means, with respect to any redemption
date, the average of two Reference Treasury Dealer Quotations for such
redemption date.

         "Quotation Agent" means the Reference Treasury Dealer appointed by the
Corporation.

         "Reference Treasury Dealer" means Chase Securities Inc. and its
successors; provided, however, that if the foregoing ceases to be a primary
U.S. Government securities dealer in New York City (a "Primary Treasury
Dealer"), the Corporation will substitute therefor another Primary Treasury
Dealer.

         "Reference Treasury Dealer Quotations" means, with respect to each
Reference Treasury Dealer and any redemption date, the average, as determined
by the Trustee, of the bid and asked prices for the Comparable Treasury Issue
(expressed in each case as a percentage of its principal


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amount) quoted in writing to the Trustee by such Reference Treasury Dealer at
5:00 p.m., New York City time, on the third business day preceding such
redemption date.

         "Treasury Rate" means, with respect to any redemption date, the rate
per annum equal to the semiannual yield to maturity of the Comparable Treasury
Issue, calculated on the third business day preceding such redemption date
using a price for the Comparable Treasury Issue (expressed as a percentage of
its principal amount) equal to the Comparable Treasury Price for such
redemption date.

         6.       Denominations; Transfer; Exchange. The Securities of this
series are in registered form without coupons in denominations of $1,000 and
any multiple of $1,000. A holder may transfer or exchange Securities in
accordance with the Indenture. The Registrar may require a holder, among other
things, to furnish appropriate endorsements and transfer documents and to pay
any taxes and fees required by law or permitted by the Indenture. Also, it need
not transfer or exchange any Securities for a period of 15 days before a
selection of Securities to be redeemed or before an interest payment date.

         7.       Persons Deemed Owners. The registered holder of this Security
may be treated as the owner of it for all purposes, and neither the Corporation,
the Trustee, nor any Registrar, Paying Agent or co-registrar shall be affected
by notice to the contrary.

         8.       Unclaimed Money. If money for the payment of principal or
interest remains unclaimed for two years, the Trustee or Paying Agent will pay
the money back to the Corporation at its request. After that, holders entitled
to unclaimed money must look only to the Corporation and not the Trustee for
payment unless an abandoned property law designates another person.

         9.       Defeasance. The Indenture contains provisions for defeasance
at any time of the entire principal of the Securities of any series upon
compliance by the Corporation with certain conditions set forth therein.

         10.      Amendment; Supplement; Waiver. Subject to certain exceptions
as therein provided, the Indenture or the Securities may be amended or
supplemented with the consent of the holders of not less than a majority in
principal amount of the Securities of each series affected, and, subject to
certain exceptions and limitations as provided in the Indenture, any past
default or compliance with any provision may be waived with the consent of the
holders of a majority in principal amount of the Securities. Without the
consent of any holder, the Indenture or the Securities may be amended or
supplemented, for among other reasons, to cure any ambiguity, omission, defect
or inconsistency, to provide for uncertificated Securities in addition to or in
place of certificated Securities or to make any change that does not materially
adversely affect the rights of any holder. Without the consent of any holder,
the Trustee may waive compliance with any provision of the Indenture or the
Securities if the waiver does not materially adversely affect the rights of any
holder.

         11.      Restrictive Covenants. The Indenture does not limit unsecured
debt of the Corporation or any of its Subsidiaries. It does limit certain
mortgages, liens and sale-leaseback


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transactions. The limitations are subject to a number of important
qualifications and exceptions. Once a year the Corporation must report to the
Trustee on compliance with the limitations.

         12.      Successors. When a successor entity assumes all the
obligations of the Corporation or its successors under the Securities and the
Indenture, the predecessor corporation will be released from those obligations.

         13.      Defaults and Remedies. An Event of Default is: default for 30
days in payment of any interest on the Securities of this series; default in
payment of any principal on the Securities of this series; failure by the
Corporation for 90 days after notice to it to comply with any of its other
agreements in the Indenture or the Securities; and certain events of bankruptcy
or insolvency. If an Event of Default with respect to Securities of this series
shall occur and be continuing, the principal of the Securities of this series
and accrued interest thereon may be declared due and payable in the manner and
with the effect provided in the Indenture. Holders of Securities may not
enforce the Indenture or the Securities except as provided in the Indenture.
The Trustee may refuse to enforce the Indenture or the Securities unless it
receives indemnity satisfactory to it. Subject to certain limitations, holders
of a majority in principal amount of the Securities may direct the Trustee in
its exercise of any trust or power. The Trustee may withhold from holders
notice of any continuing default (except a default in payment of principal or
interest) if it determines in good faith that withholding notice is in the
interests of such holders.

         14.      Trustee Dealings with the Corporation. First Union National
Bank, the Trustee under the Indenture, in its individual or any other capacity
may make loans to, accept deposits from and perform services for the
Corporation or any of its affiliates, and may otherwise deal with the
Corporation or its affiliates as if it were not Trustee.

         15.      No Recourse Against Others. A director, officer, employee or
stockholder, as such, of the Corporation shall not have any liability for any
obligations of the Corporation under the Securities or the Indenture or for any
claim based on, in respect of, or by reason of such obligations or their
creation. Each holder by accepting a Security waives and releases all such
liability. This waiver and release are part of the consideration for the issue
of the Securities.

         16.      Authentication. This Security shall not be valid until the
Trustee or other Authenticating Agent manually signs the certificate of
authentication on this Security.

         17.      Abbreviations. Customary abbreviations may be used in the
name of a holder or an assignee, such as: TEN COM (= tenants in common), TEN
ENT (= tenants by the entireties), JT TEN (= joint tenants with right of
survivorship and not as tenants in common), CUST (= Custodian) and U/G/M/A (=
Uniform Gifts to Minors Act).

         18.      Miscellaneous. This Security shall for all purposes be
governed by, and construed in accordance with, the laws of the State of New
York.

         All terms used in this Security which are defined in the Indenture
shall have the meanings assigned to them in the Indenture.


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         The Corporation will furnish to any holder upon written request and
without charge a copy of the Indenture. Requests may be made to: Martin
Marietta Materials, Inc., 2710 Wycliff Road, Raleigh, North Carolina 27607-3033
Attention: Secretary.

-------------------------------------------------------------------------------
I or we assign and transfer to

         Insert social security or other identifying number of assignee

                    [                                      ]

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-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
             (Print or type name, address and zip code of assignee)


Dated:
      -------------------------------------------------------------------------

Signed:
       ------------------------------------------------------------------------
       (Sign exactly as name appears on the front page of this Note)

Signature Guarantee:
                    -----------------------------------------------------------

Signatures must be guaranteed by an "eligible guarantor institution" meeting
the requirements of the Registrar, which requirements include membership or
participation in the Security Transfer Agent Medallion Program ("STAMP") or
such other "signature guarantee program" as may be determined by the Registrar
in addition to, or in substitution for, STAMP, all in accordance with the
Securities Act of 1934, as amended.


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