In most cases, you can use the appraised amount (but see "exceptions" in the link below and this assumes the property was not used for business or rental, which would somewhat change things).
From Publication 526:
Capital Gain Property
Property is capital gain property if you would have recognized
long-term capital gain had you sold it at fair market value on the date
of the contribution. Capital gain property includes capital assets held
more than 1 year.
Capital assets.
Capital assets include most items of property
you own and use for personal purposes or investment. Examples of capital
assets are stocks, bonds, jewelry, coin or stamp collections, and cars
or furniture used for personal purposes.
For purposes of figuring your charitable
contribution, capital assets also include certain real property and
depreciable property used in your trade or business and, generally, held
more than 1 year. You may, however, have to treat this property as
partly ordinary income property and partly capital gain property. See Property used in a trade or business under Ordinary Income Property, earlier.
Real property.
Real property is land and generally anything built on, growing on, or attached to land.
Depreciable property.
Depreciable property is property used in
business or held for the production of income and for which a
depreciation deduction is allowed.
For more information about what is a capital asset, see chapter 2 of Pub. 544.
Amount of deduction—General rule.
When figuring your deduction for a contribution
of capital gain property, you generally can use the fair market value
of the property.
Exceptions.
However, in certain situations, you must reduce
the fair market value by any amount that would have been long-term
capital gain if you had sold the property for its fair market value.
Generally, this means reducing the fair market value to the property's
cost or other basis. You must do this if:
-
The property (other than qualified appreciated stock) is contributed to certain private nonoperating foundations,
-
You choose the 50% limit instead of the special 30% limit for capital gain property, discussed later,
-
The contributed property is intellectual property (as defined earlier under Patents and Other Intellectual Property),
-
The contributed property is certain taxidermy property as explained earlier, or
-
The contributed property is tangible personal property (defined earlier) that:
-
Is put to an unrelated use (defined later) by the charity, or
-
Has a claimed value of more than $5,000 and
is sold, traded, or otherwise disposed of by the qualified organization
during the year in which you made the contribution, and the qualified
organization hasn't made the required certification of exempt use (such
as on Form 8282, Donee Information Return, Part IV). See also Recapture if no exempt use , later.
https://www.irs.gov/publications/p526#en_US_2017_publink1000229761