Depending on the situation it may be acceptable, or unacceptable, for a Canadian registered charity to issue an official donation receipt for the donation of gift certificate.  The same rules would also probably apply to a store gift card.

Here is a summary policy from CRA which set out nicely the answer:

“Gift certificates
Can a registered charity issue official donation receipts for gift certificates?
This depends on whether or not the donor is the issuer of the gift certificate. An issuer is the person (individual, retailer or business) that creates the gift certificate. A gift certificate purchased from the issuer and then donated to a charity is considered property and may be receipted for its eligible amount. However, a certificate donated by the issuer is not property, but rather a promise, and may not be receipted.
Registered charities can issue an official donation receipt when:
• the donor is not the issuer of the gift certificate; and
• the donor has purchased the gift certificate either from the issuer or another third party.
References
• CPS-018, Donations of Gift Certificates”

Here is a more detailed policy statement from CRA on gift certificates:

“Policy Statement
Donations of Gift Certificates
Reference Number
CPS – 018
Effective Date
October 9, 2002
Purpose
This policy statement outlines the Directorate’s policy on circumstances where official donation receipts for income tax purposes can be issued for gift certificates.
Statement
Registered charities can issue official donation receipts for income tax purposes for gift certificates.
Definitions
gift certificate: a certificate having a stated monetary value that entitles the recipient to purchase goods and/or services in the establishment of the issuer
issuer: the person (individual, retailer, business) that creates a gift certificate redeemable for goods and/or services from that person
Implementation
1. This policy applies to registered charities that issue official donation receipts for gift certificates. Registered charities often accept gift certificates and use them in fundraising events, such as auctions and raffles.
2. Registered charities can issue an official donation receipt when the donor
a. is not the issuer of the gift certificate; and
b. has obtained the gift certificate for valuable consideration either from the issuer or other third party.
3. Registered charities cannot issue official donation receipts for gift certificates they receive directly from the issuer.
4. A charitable donation must involve a transfer of property[Footnote 1] of any kind, real or personal, corporeal or incorporeal, which includes rights. A right is a legally enforceable claim by one person against another. Whether the donation of a gift certificate constitutes a transfer of property, and more particularly a transfer of a right, depends on the particular circumstances.
5. A gift certificate can be considered to be a promise from a merchant to supply goods and/or services in an amount specified on the face of the certificate. The Canada Revenue Agency has determined that a gift certificate constitutes property and a right, but only if the promise is enforceable, that is, only when the certificate was acquired for consideration.
Scenarios
6. When a person purchases, or otherwise obtains for consideration, a gift certificate, the terms of which permit its assignment, from an issuer and donates it to a charity, the purchaser/donor can receive an official donation receipt for the fair market value of the gift certificate. A receipt cannot be issued to the issuer of the gift certificate. It is the purchaser/donor who has made a donation of the gift certificate to the charity and not the issuer.
In this scenario, the issuer of the gift certificate will realize income for the fair market value of the gift certificate.
7. When the issuer donates a gift certificate directly to a charity, the issuer is not entitled to an official donation receipt at the time the donation is made. This concept is further developed in paragraph 9 below.
In this scenario, the donation does not constitute a transfer of property and the issuer does not realize any income for having donated the gift certificate.
8. When the issuer donates a gift certificate directly to a charity, the issuer may be eligible for an official donation receipt when the charity redeems the certificate for property. Therefore, to be eligible for a receipt, redemption of the certificate must form a transaction that would otherwise have constituted a gift. In other words, the charity must redeem the certificate for some form of property. A receipt cannot be issued if the charity redeems the gift certificate for a contribution of services[Footnote 2], such as time, skills or effort, because these are not property and do not qualify as charitable donations. A receipt issued by the charity should specify the nature of the property it received in exchange for the gift certificate.
In this scenario, the issuer of the gift certificate will realize income equal to the difference between the value of the property gifted and the amount it paid for the property.
9. When the issuer donates a gift certificate directly to a charity, and the charity transfers the certificate to a third party, for example, at an auction or a raffle, the redemption of the gift certificate by the third party does not entitle the issuer to a receipt. The honouring of the gift certificate by the retailer cannot transform the character of the original transfer of the gift certificate to the charity into a gift. Each transaction must be viewed independently in determining whether a gift has been made.
In this scenario, no income is realized in respect of the donation and no donation deduction or tax credit can be claimed. However, where the issuer has donated and redeemed a gift certificate for property for the purpose of earning income in its business, a reasonable deduction may be available in respect of the cost of the property[Footnote 3].
Value of a gift certificate
10. The Canada Revenue Agency has determined that in some instances, the fair market value of a gift certificate may not be the equivalent of its face value. Factors to consider might be:
a. the flexibility of the certificate – does the coupon expire after a certain time, is it usable only within a specific timeframe, does it restrict the purchaser to specific merchandise within the store, and
b. its usefulness – does the retailer offer merchandise for the amount of the gift certificate, or will the certificate account for a portion of regular selling property, for example, a $50 gift certificate at a car dealership.
Such factors may reduce the fair market value of a gift certificate. Where a charity is redeeming a gift certificate, donated by a retailer, the receipt should be issued for the fair market value of the property supplied.
References
• Income Tax Act, R.S.C. 1985, (5th supp.) c.1.
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Footnotes
[Footnote 1]
Income Tax Act, ss. 248(1).
[Footnote 2]
Gifts and Official Donation Receipts, IT-110.
[Footnote 3]
Income Tax Act, s. 9.”