INDUSTRIAL SPACE LEASE

Exhibit 10.13

INDUSTRIAL SPACE LEASE

THIS LEASE, made and entered into in Chicago, Illinois as of this 29 day of July, 2005 by and between Rubicon Technology, Inc. (“Tenant”), and Radion Mogilevsky and Nanette Mogilevsky (“Landlord”);

W I T N E S S E T H :

1. Basic Terms . This Section 1 contains the basic terms of the Lease between Landlord and Tenant. All other provisions of this Lease are to be read in accordance with the provisions herein contained.

2. Lease of Premises and Term . Landlord hereby leases to Tenant, and Tenant hereby accepts the premises, consisting of the land and improvements commonly known as 9931 Franklin Avenue, Franklin Park, Illinois (“Premises”), commencing on the Commencement Date set forth in Section 1 hereof and continuing for a period of five (5) years thereafter and terminating on the Termination Date (“Term”).

3. Rent . Tenant shall pay the Monthly Rent set forth in Section 1 to Landlord at the address set forth in Section 1 hereof or to such other person or at such other place as Landlord may direct in writing, in advance on or before the first day of each month of the term. Monthly Rent, together with all other amounts due hereunder, are sometimes referred to as “Rent.” In the event the Commencement Date or the Termination Date is a day other than the first day of a month, Rent shall be prorated based on the number of days remaining in such month. Except with respect to those obligations for which Landlord is specifically made responsible hereunder, this Lease is intended to be a “net lease” with Tenant responsible for all costs relating to the Premises, including but not limited to repair and maintenance costs and insurance premiums.

4. Utilities/Taxes .

A. Tenant shall pay, directly to the appropriate supplier, all costs of all natural gas, electricity, heat, light, power, sewer service, telephone, water, refuse disposal and other utilities and services supplied to the Premises. Landlord shall not in any way be liable or responsible to Tenant for any loss or damage or expense which Tenant may sustain or incur if either the quantity or character of such service is changed or is no longer available or suitable for Tenant’s requirements. Within one (1) week after Landlord’s request therefor, but in any event on a monthly basis not more often than once in any calendar quarter, Tenant shall deliver copies of the utility bills together with evidence of the full and timely payment of such utility bills.

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B. Tenant shall pay all real estate taxes (the “Taxes”) levied or assessed against the Premises that are due and payable during the Term. Landlord shall deliver copies of all bills for the Taxes and Tenant shall pay the Taxes prior to the due date therefore. Promptly after payment Tenant shall provide Landlord with receipts for or other satisfactory evidence of payment of the Taxes. Tenant may pay such taxes “under protest” or otherwise contest the amount of such bills so long as Tenant complies with the statutory provisions for doing so and the taxes are not considered delinquent and so long as Tenant provides Landlord with security, reasonably satisfactory to Landlord, that the unpaid taxes will be paid at the conclusion of the protest or other contest.

5. Condition of Premises . Tenant is currently in possession of the Premises and is deemed to have accepted possession of the Premises in the order and condition as now exists. No promise of Landlord to alter, remodel, decorate, clean or improve the Premises has been made by Landlord to Tenant nor has Landlord made any representation respecting the condition of the Premises.

6. Care and Maintenance . Tenant shall, at Tenant’s own expense, keep and maintain the roof and structural members of the building in which the Premises are in good order and repair and in full compliance with all laws and ordinances applicable to the Premises, ordinary wear and tear and loss by fire or other casualty excepted; provided, however, except to the extent caused by the negligence or intentional misconduct of Tenant, Tenant shall not be required to replace the roof or make structural repairs the cost of which is reasonably estimated to exceed $100,000. In addition, Tenant shall, at Tenant’s own expense, keep the Premises, parking areas, sidewalk, landscaping and all other areas associated with the Premises in good order, condition and repair. Tenant shall promptly arrange with Landlord, at Tenant’s sole expense, for the repair of all damage to the Premises and for the maintenance, replacement or repair of the Premises, with materials equal in quality and class to the materials in place as of the Commencement Date. If Tenant does not promptly make such arrangements, after fifteen (15) days of notice to Tenant specifying the work Landlord believes is required and Tenant’s continued failure to make such repairs or replacements (except in the case of an emergency when no notice shall be required), Landlord may, but need not, make such repairs and replacements and one hundred twenty-five percent (125%) of Landlord’s cost for such repairs and replacements shall be deemed Additional Rent reserved under this Lease due and payable forthwith.

7. Alterations . Tenant shall not make any structural alterations (not including ordinary repairs or replacements) to the Premises or to any of the major building systems serving the Premises without Landlord’s prior written consent in each and every instance, which will not be unreasonably withheld or delayed. When considering a request by Tenant for approval of an alteration, Landlord shall grant its approval if the alteration is necessary, in Tenant’s reasonable opinion, for the operation of Tenant’s business, will not adversely affect the structural elements or the major building systems serving the Premises, and will be removable upon a termination of the Lease, it being understood and agreed by Tenant that it must, at the termination of the Lease, remove such alterations and repair any damage caused by such alteration or the removal of the alteration. Landlord acknowledges that Tenant made alterations to the Premises during the term of the prior lease of the Premises between Landlord and Tenant and Landlord hereby accepts such alterations and waives any claim that it may have or may have had with respect to such alterations.

8. Access to Premises . Tenant shall permit Landlord, its agents and designees, to have free access to the Premises and any part thereof upon 24 hours’ notice to Tenant, except in the event of an

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emergency when no advance notice shall be necessary but Landlord shall use its reasonable efforts to notify (which may be verbally) Tenant of the need for such access. Landlord or Landlord’s agents shall have the right to enter upon the Premises to inspect the same and to make such repairs to the Premises that Tenant is required to make hereunder, but has not, as provided in Section 6 above, and Landlord shall be allowed to take all material into and upon said Premises as may be required therefor without the same constituting an eviction of Tenant. Rent shall not abate while said repairs are being made. Nothing herein contained, however, shall be deemed or construed to impose upon Landlord any obligations, responsibilities or liabilities whatsoever for the care, supervision or repair of the Premises or any part thereof in the exercise of any rights herein provided.

9. Insurance . During the entire Term hereof Tenant shall carry commercial general liability insurance and casualty insurance (on a full replacement cost basis) and otherwise in such amounts and with such companies as may be reasonably acceptable to Landlord and, absent a material change in Tenant’s operations, in line with the coverages maintained by Tenant with Landlord’s approval under the previous lease of the Premises between Tenant and Landlord. All such policies shall insure Tenant, and insure Landlord as an additional named insured as its interests may appear.

10. Subrogation . Tenant agrees to have all fire and extended coverage and material damage insurance which may be carried by it endorsed with a clause providing that any release from liability of or waiver of claim for recovery from Landlord entered into in writing by the insured thereunder prior to any loss or damage shall not affect the validity of said policy or the right of the insured to recover thereunder, and providing further that the insurer waives all rights of subrogation which such insurer might have against Landlord. Without limiting any release or waiver of liability or recovery contained in any other Section of this Lease, Tenant waives all claims for recovery from Landlord, any beneficiaries of Landlord and the managing agent for the Premises and their respective agents, partners and employees, for any loss or damage to any of its property insured under valid and collectible insurance policies to the extent of any recovery collectible under such insurance policies. Notwithstanding the foregoing or anything contained in this Lease to the contrary, any release or any waiver of claims shall not be operative, nor shall the foregoing endorsements be required, in any case where the effect of such release or waiver is to invalidate insurance coverage or invalidate the right of the insured to recover thereunder or increase the cost thereof (provided that in the case of increased cost the other party shall have the right, within ten (10) days following written notice, to pay such increased cost, thereby keeping such release or waiver in full force and effect).

11. Casualty . If the Premises or the Building are damaged by fire or other casualty, Tenant shall repair, restore or rehabilitate the Building or the Premises at Tenant’s expense, using, to the extent available, any insurance proceeds payable as a result of the fire or other casualty; provided, however, that if more than 25% of the Premises are rendered untenantable as a result of such fire or other casualty, then Landlord may elect to terminate this Lease by delivering written notice to Tenant within sixty (60) days of such damage. If such fire or other casualty shall render more than 25% of the Premises untenantable during the last year of the term of this Lease or if all the proceeds from insurance are not made available to Tenant by Landlord or Landlord’s mortgagee, Tenant may elect to terminate this Lease by delivering notice to Landlord within sixty (60) days of the date of such fire or casualty. If this Lease is terminated pursuant to these provisions, Rent shall be apportioned on a per diem basis and paid to the date of the fire or other casualty.

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12. Eminent Domain

A. If a portion of the Building or the Premises shall be lawfully taken or condemned for any public or quasi-public use or purpose, or conveyed under threat of such condemnation and as a result thereof the Premises cannot be used for the same purpose and with the same utility as before such taking or conveyance, the terms of this Lease shall end upon, and not before, the date of the taking of possession by the condemning authority, and without apportionment of the award. Tenant hereby assigns to the Landlord, Tenant’s interest in such award, if any. Current rent shall be apportioned as of the date of such termination. If any part of the Building shall be so taken or condemned, or if the grade of any street or alley adjacent to the Building is changed by any competent authority and such taking or change of grade makes it necessary or desirable to demolish, substantially remodel, or restore the Building, the Landlord shall have the right to cancel this Lease upon not less than ninety (90) days’ prior notice to the date of cancellation designed in the notice.

B. If a portion of the Premises shall be lawfully taken or condemned or conveyed under threat of condemnation but thereafter the Premises can be used by Tenant for the same purpose and with substantially the same utility, this Lease shall not be terminated and Landlord shall repair the Premises (but Landlord shall not be required to expend more on such repair than the amount of the condemnation award), and the Lease shall be amended to equitably reduce the Base Rent. No money or other consideration shall be payable by the Landlord to the Tenant for any right of cancellation or temporary taking, and the Tenant shall have no right to share in any condemnation award or to share in any judgment for damages caused by a change of grade.

13. Tenant’s Indemnity and Waiver . Tenant will protect, indemnify and save Landlord, its partners, shareholders, employees, officers, directors, agents, and their respective successors and assigns harmless from and against all liabilities, obligations, claims, damages, penalties, causes of action, costs and expenses (including without limitation, reasonable attorney’s fees and expenses) imposed upon, incurred by or asserted against Landlord by reason of: (a) any accident, injury to or death of persons or loss of or damage to property occurring on or about the Premises or any part thereof or the adjoining properties, sidewalks, curbs, streets or ways, or resulting from an act or omission of Tenant or anyone claiming by through or under Tenant; (b) any failure on the part of Tenant to perform or comply with any of the terms of this Lease or any other agreements affecting the Premises; (c) the use, occupation, condition or operation of the Premises or any part thereof; or (d) performance of any labor or services or the furnishing of any materials or other property in respect of the Premises or any part thereof. In case any action, suit or proceeding is brought against Landlord by reason of any such occurrence, Tenant will, at Tenant’s sole expense, resist and defend such action, suit or proceeding, or cause the same to be resisted and defended.

Tenant waives all claims it may have against Landlord and Landlord’s agents for damage or injury to person or property sustained by Tenant or any persons claiming through Tenant or by any occupant of the Premises, or by any other person, resulting from any part of the Premises becoming out of repair, or resulting from any accident on or about the Premises or resulting directly or indirectly from any act or neglect of any person, including Landlord to the extent permitted by law.

This Section 13 shall include, but not by way of limitation, damage caused by water, snow, frost, steam, excessive heat or cold, sewage, gas, odors or noise, or caused by bursting or leaking pipes or plumbing fixtures, and shall apply equally whether any such damage results from the act or neglect of Tenant or of any other person, including Landlord to the extent permitted by law, and whether such damage be caused or result from anything or circumstance above mentioned or referred to, or to any other thing or circumstance whether

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of a like nature or of a wholly different nature. All personal property belonging to Tenant or any occupant of the Premises shall be there at the risk of Tenant or of such other person only, and Landlord shall not be liable for any damage thereto or for the theft or misappropriation thereof.

14. Assignment/Subletting . Tenant shall not, without Landlord’s prior written consent, which in each instance, may be withheld at the sole discretion of Landlord: (i) assign, transfer or convey this Lease or any interest under it; (ii) allow any transfer of, or any lien upon, Tenant’s interest in this Lease by operation of law; (iii) sublet the Premises in whole or in part; or (iv) allow the use or occupancy of any portion of the Premises by anyone other than Tenant or Tenant’s employees; provided that, i