<PAGE>
                                                                   EXHIBIT 10.13


        THIS NOTE HAS BEEN ACQUIRED FOR INVESTMENT PURPOSES ONLY AND MAY NOT BE
TRANSFERRED UNTIL (i) A REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933,
AS AMENDED (THE "ACT") SHALL HAVE BECOME EFFECTIVE WITH RESPECT THERETO OR (II)
THE ISSUER SHALL HAVE RECEIVED AN OPINION OF COUNSEL OR OTHER EVIDENCE
REASONABLY SATISFACTORY TO THE ISSUER TO THE EFFECT THAT REGISTRATION UNDER THE
ACT IS NOT REQUIRED IN CONNECTION WITH SUCH PROPOSED TRANSFER NOR IS SUCH
TRANSFER IN VIOLATION OF ANY APPLICABLE STATE SECURITIES LAWS. THIS LEGEND SHALL
BE ENDORSED UPON ANY NOTE ISSUED IN EXCHANGE FOR THIS NOTE. THIS NOTE IS SUBJECT
TO FURTHER RESTRICTIONS ON TRANSFER SET FORTH HEREIN.

        THIS CONVERTIBLE SUBORDINATED NOTE AND THE INDEBTEDNESS EVIDENCED
HEREBY, AND THE EXERCISE OF RIGHTS AND REMEDIES HEREUNDER, ARE SUBORDINATE IN
THE MANNER AND TO THE EXTENT SET FORTH IN THIS NOTE.

                         AMERICAN STONE INDUSTRIES, INC.

                       6.00% CONVERTIBLE SUBORDINATED NOTE

                               DUE OCTOBER 1, 2004

DATE OF ISSUANCE:  OCTOBER 1, 2002                                      $150,000

        AMERICAN STONE INDUSTRIES, INC., a Delaware corporation (the "Company"),
for value received, hereby promises to pay to ROULSTON VENTURES LIMITED
PARTNERSHIP (the "Payee") on October 1, 2004 (the "Maturity Date") at the
principal office of the Company, 8705 Quarry Road, Amherst, Ohio 44001, the
principal amount of One-Hundred and Fifty Thousand Dollars ($150,000), which
shall be payable in cash or by check on the terms set forth herein. Simple
interest on the principal amount of this Note shall be paid at the rate of six
percent (6.00%) per annum accrued through the Maturity Date, and payable in cash
or by check quarterly in arrears commencing January 1, 2003 and each, April 1,
July 1, October 1 and January 1, thereafter. The principal amount of this Note
and all interest accrued hereon shall be payable on the Maturity Date.

        The Payee hereby irrevocably subscribes for and agrees to purchase this
Note and agrees to transfer on the date hereof to an account specified by the
Company immediately available funds in the principal amount of this Note.

        1. CONVERSION INTO SHARES OF COMMON STOCK. The Payee shall be entitled,
at its option, at any time on or before the close of business on the Maturity
Date to convert this Note (or any portion of the principal amount hereof that is
$1,000 or an integral multiple thereof), at the principal amount hereof, or of
such portion, into fully paid and non-assessable shares (calculated as to each
conversion to the nearest 1/100th of a share) of Common Stock, par value

                                  Exhibit 10.13
                                   Page 1 of 9
<PAGE>

$.00l per share (the "Common Stock") of the Company at a conversion price equal
to Five Dollars ($5.00) principal amount for each share of Common Stock (or at
the current adjusted conversion price if an adjustment has been made as provided
in the following paragraph) (the "Conversion Price") by surrender of this Note,
duly endorsed or assigned to the Company or in blank, to the Company at its
office, accompanied by written notice to the Company in the form provided in
this Note (or such other notice as is acceptable to the Company) that the Payee
elects to convert this Note, or if less than the entire principal amount hereof
is to be converted, the portion hereof to be converted. No fractional shares of
Common Stock will be issued on conversion, but instead of any fractional share,
the Company shall pay a cash adjustment in an amount equal to the Conversion
Price.

        2. ADJUSTMENT OF CONVERSION PRICE. The Conversion Price shall be
equitably adjusted upon the occurrence on or before the Maturity Date of (i) the
issuance of additional shares of Common Stock as a stock dividend or other
distribution on outstanding shares of Common Stock, (ii) a subdivision of
outstanding shares of Common Stock into a greater number of shares of Common
Stock, or (iii) a combination or reverse stock split of outstanding shares of
Common Stock into a smaller number of shares of Common Stock. The Conversion
Price as so adjusted, shall be readjusted in the same manner upon the happening
of any successive stock dividend, stock split or similar event on or before the
Maturity Date.

        3. CHANGE IN CONTROL. Upon any Change in Control (as hereinafter
defined) that occurs before the Maturity Date, the Company, or any different
entity which is the surviving entity in any transaction that constitutes a
Change in Control, shall repay to the Payee (the "Contingent Repayment") the
entire principal amount of this Note, together with interest due thereon through
and including the effective date of such Change in Control (the "Change in
Control Date"). The Company (or such entity) shall make the Contingent Repayment
to the Payee in immediately available funds on the Change in Control Date, and
the Payee shall transmit and surrender the original of this Note to the Company
thereupon for cancellation. Notwithstanding the foregoing, upon a Change in
Control, the Payee shall have the right, at its option, to convert this Note
pursuant to the terms of Paragraph 1 above, in lieu of its right to receive the
Contingent Repayment.

        For the purposes of this Note, a "Change in Control" shall mean the
occurrence at any time before the Maturity Date of any of the following events:

           (a) The Company is merged or consolidated or reorganized into or with
another corporation or other legal person or entity (other than the Payee or any
affiliate of the Payee), and as a result of such merger, consolidation or
reorganization, less than a majority of the combined voting power of the
then-outstanding securities of such corporation, person or entity immediately
after such transaction are held in the aggregate by the holders of the
then-outstanding securities entitled to vote generally in the election of the
Company's directors ("Voting Stock") immediately prior to such transaction;

           (b) The Company sells or otherwise transfers all or substantially all
of its assets to any other corporation or other legal person or entity (other
than the Payee or any affiliate of the Payee), and less than a majority of the
combined voting power of the then-outstanding securities of such acquiring
corporation, person or entity immediately after such sale or transfer is held in
the aggregate by the holders of Voting Stock immediately prior to such sale or
transfer; or
                                  Exhibit 10.13
                                   Page 2 of 9
<PAGE>

           (c) Any person (as the term "person" is used in Section 1 3(d)(3) of
the Securities Exchange Act of 1934, as amended (the "Exchange Act")), other
than (i) the Payee, (ii) any affiliate of the Payee, (iii) any group including
the Payee, or (iv) any acquiror of Voting Stock from the Payee or any affiliate
of the Payee, has become the beneficial owner (as the term "beneficial owner" is
defined under Rule 13d-3 or any successor rule or regulation promulgated under
the Exchange Act) of securities representing 50% or more of the total votes
comprising the Voting Stock.

           Notwithstanding the foregoing, a Change of Control shall not be
deemed to occur as a result of any transaction actively promoted or supported by
the Payee or any affiliate of the Payee.

        4. POSITIVE COVENANTS OF THE COMPANY. The Company covenants and agrees
that, on or before the Maturity Date it shall:

           (a) Promptly pay and discharge all material and lawful taxes,
assessments, and governmental charges or levies imposed upon the Company or upon
its income and profits, or upon any of its property, before the same shall
become in default, as well as all material and lawful claims for labor,
materials and supplies that, if unpaid, might become a lien or charge upon such
properties or any part thereof, except where the failure to comply would not
have a material adverse effect on the Company and except that the Company shall
not be required to pay and discharge any such tax, assessment, charge, levy or
claim so long as the validity thereof shall be contested in good faith by the
Company;

           (b) Do or cause to be done all things reasonably necessary to
preserve and keep in full force and effect its corporate existence, rights and
franchises and comply with all material laws applicable to the Company, except
where the failure to comply would not have a material adverse effect on the
Company;

           (c) At all times reasonably maintain, preserve, protect and keep its
material property used or useful in the conduct of its business in good repair,
working order and condition, and from time to time make all needful and proper
repairs, renewals, replacements and improvements thereto as shall be reasonably
required in the conduct of its business, except where the failure to comply
would not have a material adverse effect on the Company;

           (d) To the extent necessary for the operation of its business, keep
adequately insured by financially sound reputable insurers, all material
property of a character usually insured by similar corporations and carry such
other insurance as is usually carried by similar corporations, except where the
failure to obtain insurance would not have a material adverse effect on the
Company;

           (e) Prior to the issuance of any Common Stock hereunder, reserve for
issuance a sufficient number of authorized but unissued shares of Common Stock
to allow for their issuance hereunder upon conversion of this Note; and

           (f) At all times keep true and correct books, records and accounts.

                                  Exhibit 10.13
                                   Page 3 of 9
<PAGE>

        5. REPRESENTATIONS AND WARRANTIES OF THE PAYEE.

           (a) GENERAL. The Payee understands and acknowledges that the Note and
the securities into which it is convertible are being offered and sold under one
or more of the exemptions from registration provided for in Section 4(2) of the
Securities Act of 1933, as amended (the "Securities Act") and any applicable
state securities laws. The Payee is purchasing the Note without being offered or
furnished any formal offering literature or prospectus. The Payee understands
that this transaction has not been reviewed or approved by the Securities and
Exchange Commission or by any state regulatory authority charged with the
administration of the securities laws of any state. All documents, records and
books pertaining to this investment, as well as management of the Company, have
been made available to the Payee and the representatives of the Payee, and the
books and records of the Company will be available upon reasonable notice for
inspection by the Payee during reasonable business hours at its principal
offices set forth above.

           (b) SUITABILITY. The Payee confirms that the Payee understands and
has fully considered for purposes of this investment the risks of this
investment and understands that (i) this investment is suitable only for an
investor who is able to bear the economic consequences of losing his or her
entire investment, (ii) the purchase of the Note and the Common Stock is a
speculative investment that involves a high degree of risk, and (iii) there are
substantial restrictions on the transferability of, and there will be no
immediate public market for, the Note, and accordingly, it may not be possible
for the Payee to liquidate the Payee's investment in case of emergency.

           (c) LACK OF LIQUIDITY. The Payee confirms that the Payee is able (i)
to bear the economic risk of this investment, and (ii) to hold the Note and the
Common Stock for an indefinite period of time. The Payee has sufficient liquid
assets so that the illiquidity associated with this investment will not cause
any undue financial difficulties or affect the Payee's ability to provide for
the Payee's current needs and possible financial contingencies, and that the
Payee's commitment to all speculative investments is reasonable in relation to
the Payee's net worth and annual income.

           (d) KNOWLEDGE AND EXPERIENCE. The Payee has such knowledge and
experience in financial and business matters that the Payee is capable of
evaluating the merits and risks of this speculative investment and of making an
informed investment decision.

           (e) ACCREDITED INVESTOR. The Payee is an "accredited investor" as
defined in Rule 501 of Regulation D under the Securities Act

           (f) ACCESS TO MANAGEMENT. The Payee confirms that, in making the
decision to purchase the Note and/or the Common Stock, the Payee has relied
solely upon independent investigations made by the Payee, and that the Payee has
been given the opportunity to ask questions of, and to receive answers from,
management and other persons acting on behalf of the Company concerning the
Company.

           (g) INVESTMENT INTENT. The Note and the Common Stock are being
acquired by the Payee solely for the personal account of the Payee, for
investment purposes only, and not with a view to, or in connection with, any
resale or distribution thereof. The Payee has no

                                  Exhibit 10.13
                                   Page 4 of 9
<PAGE>

contract, undertaking, understanding, agreement or arrangement, formal or
informal, with any person to sell, transfer or pledge to any person the Note or
the Common Stock, or any part thereof, or any interest therein or any rights
thereto. The Payee has no present plans to enter into any such contract,
undertaking, agreement or arrangement. The Payee must bear the economic risk of
the investment for an indefinite period of time because the Note and the Common
Stock have not been registered under the Securities Act and applicable state
securities laws and, therefore, cannot be sold unless it is subsequently
registered under the Securities Act and applicable state securities laws or
unless an exemption from such registration is available.

           (h) RESTRICTIVE LEGEND. The Payee consents to the placement of a
restrictive legend on the certificate(s) representing the Common Stock issued
upon conversion hereof to reflect the restrictions on transfer provided under
applicable securities laws.

           (i) BROKERS. The Payee has not incurred on its own account, or on
account of the Company, any obligation to pay any broker's fee or commission in
connection with this investment.

           (j) INVESTMENT COMMITMENT NOT DISPROPORTIONATE TO NET WORTH. The
Payee's overall commitment to investments that are not readily marketable is not
disproportionate to the Payee's net worth and the Payee's investment in the
Company will not cause such overall commitment to become excessive.

           (k) SURVIVAL OF REPRESENTATIONS, WARRANTIES AND ACKNOWLEDGMENTS. The
representations and warranties of the Payee contained in this Section 5 are true
and accurate as of the date hereof and shall be true and accurate as of the date
of issuance of the Common Stock.

        6. WITHHOLDING. The Company shall be entitled to withhold from all
payments of principal of, and interest on, this Note any amounts required to be
withheld under the applicable provisions of the United States income tax laws or
other applicable law at the time of such payments.

        7. OBLIGATIONS ABSOLUTE. No provision of this Note shall alter or impair
the obligation of the Company, which is absolute and unconditional, to pay the
principal of, and interest on this Note at the time, place and rate, and in the
security, coin or currency, herein prescribed. This Note is a direct obligation
of the Company.

        8. NO RECOURSE AGAINST INDIVIDUALS. No recourse shall be available for
the payment of the principal of, or the interest on this Note, or for any claim
based hereon, or otherwise in respect hereof, against any incorporator,
stockholder, officer, employee or director, as such, past, present or future, of
the Company or any successor corporation, whether by virtue of any constitution,
statute or rule of law, or by the enforcement of any assessment or penalty or
otherwise, all such liability being, as part of the consideration for the issue
hereof, expressly waived. The obligation of the Company on this Note is primary
and exclusive.

        9. COMPLIANCE WITH SECURITIES LAWS. The Payee agrees that this Note is
being acquired for investment and that the Payee shall not offer, sell,
transfer, assign, exchange or otherwise dispose of this Note or the shares of
Common Stock issuable upon conversion hereof

                                  Exhibit 10.13
                                   Page 5 of 9

<PAGE>

except under circumstances that will not result in a violation of the Securities
Act or any applicable state Blue Sky law or similar laws relating to the sale or
transfer of securities.

        10. DEFAULT CONDITIONS. This Note shall become and be due and payable
upon written demand made by the Payee if one or more of the following events,
herein called events of default, shall happen and be continuing:

           (a) Default in the due observance or performance of any material
covenant, condition or agreement on the part of the Company to be observed or
performed pursuant to the terms hereof and such default shall continue uncured
for 30 days after written notice thereof, specifying such default, shall have
been given to the Company by the Payee;

           (b) Application for, or consent to, the appointment of a receiver,
trustee or liquidator of the Company or of its property;

           (c) Admission in writing of the Company's inability to pay its debts
as they mature;

           (d) General assignment by the Company for the benefit of creditors;

           (e) Filing by the Company of a voluntary petition in bankruptcy or a
petition or an answer seeking reorganization, or an arrangement with creditors;

           (f) Entering against the Company of a court order approving a
petition filed against it under the federal or state bankruptcy laws, which
order shall not have been vacated or set aside or otherwise terminated within 60
days; or

           (g) Non-payment under the terms of Section 3 hereof on the Change of
Control Date.

        11. NOTICE OF DEFAULT. The Company agrees that notice of the occurrence
of any event of default shall be promptly given to the Payee.

        12. ENFORCEMENT OF RIGHTS. In case any one or more of the events of
default specified above shall happen and be continuing, the Payee may proceed to
protect and enforce its rights by suit in the specific performance of any
covenant or agreement contained in this Note or in aid of the exercise of any
power granted in this Note or may proceed to enforce the payment of this Note or
to enforce any other legal or equitable rights as such Payee.

        13. PAYMENTS. Whenever any payment to be made shall be due on a
Saturday, Sunday or a public holiday under the laws of the Commonwealth of
Delaware, such payment may be made on the next succeeding business day, and such
extension of time shall in such case be included in the computation of payment
of interest due.

        14. NO TRANSFER OR EXCHANGE OF NOTES. The Company agrees not to transfer
or assign the obligations under this Note, or any interest herein, by operation
of law or otherwise, without the prior written consent of the Payee, which
consent shall not be unreasonably withheld. The Payee agrees not to transfer,
assign, negotiate or exchange this Note, or any interest herein,




                                  Exhibit 10.13
                                   Page 6 of 9


<PAGE>

by operation of law or otherwise, without the prior written consent of the
Company, which consent shall not be unreasonably withheld.

        15. REPLACEMENT OF NOTE. Upon receipt from the Payee of evidence
satisfactory to the Company of the loss, theft, destruction or mutilation of the
Note and, if requested by the Company in the case of any such loss, theft or
destruction, upon delivery of an indemnity bond or other agreement or security
reasonably satisfactory to the Company, or, in the case of any such mutilation,
upon surrender and cancellation of the Note, the Company shall issue a
substitute Note to the Payee, of like tenor and amount and dated the date hereof
in lieu of such lost, stolen, destroyed or mutilated Note.

        16. AUTHORIZATION. This Note has been issued by the Company pursuant to
authorization of the Board of Directors of the Company.

        17. PRESENTATION FOR PAYMENT. Payment of principal and interest, whether
in cash or by check, shall be made to the Payee as set forth herein upon
presentation and surrender of this Note upon or after maturity.

        18. WAIVER; AMENDMENT. No provision of this Note may be waived, amended,
modified, superseded, canceled, terminated, renewed or extended except in a
written instrument signed by the party against whom any of the foregoing action
is asserted. Any waiver shall be limited to the particular instance and for the
particular purpose when and for which it is given.

        19. SEVERABILITY: REFORM. The invalidity, illegality or unenforceability
of any provision of this Note shall in no way effect the validity, legality or
enforceability of any other provision of this Note and this Note shall be
construed and reformed by any court of competent jurisdiction to give full
effect to the essential purposes of this Note.

        20. NOTICES. All notices provided for in this Note shall be given in
writing and shall be effective when given by personal delivery or by electronic
facsimile transmission (with receipt thereof electronically confirmed), or the
next business day after delivery to an nationally recognized express overnight
courier service, or three business days after being sent by first class mail,
postage prepaid, addressed to the parties at their respective addresses herein
set forth, or to such other address or addresses as either party may later
specify by written notice to the other.

        21. COUNTERPARTS. This Note may be executed in duplicate counterparts,
which, when taken together, shall constitute one instrument, but only the
original counterpart executed by a duly authorized representative of the Company
shall be deemed to be an original instrument for purposes of enforcing this Note
against the Company.

        22. DISPUTE RESOLUTION. Any dispute, controversy or claim arising out
of, in connection with, or in relation to this Note or the breach of any of the
provisions hereof shall be settled by arbitration in Cleveland, Ohio, pursuant
to the rules then obtaining of the America Arbitration Association. Any award
shall be final, binding and conclusive upon the parties and a judgment rendered
thereon may be entered in any court having competent jurisdiction thereof.

                                  Exhibit 10.13
                                   Page 7 of 9

<PAGE>

        23. GOVERNING LAW. This Note shall be construed and enforced in
accordance with, and the rights of the parties shall be governed by, the laws of
the State of Delaware, without regard to the conflict of laws principles
thereof.

        24. ENTIRE AGREEMENT. This Note constitutes the entire agreement between
the Company and the Payee relative to the subject matter hereof, and supersedes
all proposals or agreements, written or oral, and all other communications
between the parties relating to the subject matter of this Note.

        IN WITNESS WHEREOF, the Company and the Payee have caused this Note to
be executed, as of the date first set forth above, by their duly authorized
representatives.

ROULSTON VENTURES LIMITED PARTNERSHIP
           (the "Payee")




BY:     /s/ Thomas H. Roulston II
   ----------------------------------------
NAME:   THOMAS H. ROULSTON II
TITLE:  GENERAL PARTNER


PRINCIPAL BUSINESS ADDRESS OF PAYEE:


                        3636 Euclid Avenue
                        Cleveland, Ohio  44103


AMERICAN STONE INDUSTRIES, INC.
       (THE "COMPANY")




BY:         /s/ Russell H. Ciphers
   ---------------------------------------------------------
NAME:          Russell H. Ciphers
     -------------------------------------------------------
TITLE:         President
      ------------------------------------------------------


                                  Exhibit 10.13
                                   Page 8 of 9



<PAGE>


                                CONVERSION NOTICE

                       TO AMERICAN STONE INDUSTRIES, INC.


The undersigned Payee of this Note hereby irrevocably exercises the option to
convert this Note, or the portion hereof (which is $1,000 or a multiple thereof)
designated below, into shares of Common Stock in accordance with the terms of
the Note, and directs that the shares issuable and deliverable upon the
conversion, together with any cash or check in payment for a fractional share
and any Note representing any unconverted principal amount hereof, be issued and
delivered to the registered owner hereof unless a different name has been
provided below.


Dated:____________________________              ____________________________
                                                         Signature(s)








                                                Principal amount to be converted
                                                             (if less than all):
                                                                 $__________,000


                                  Exhibit 10.13
                                   Page 9 of 9