<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2013-09-18</periodOfReport>

    <dateOfOriginalSubmission>2013-09-20</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001084226</issuerCik>
        <issuerName>Searchlight Minerals Corp.</issuerName>
        <issuerTradingSymbol>SRCH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001316580</rptOwnerCik>
            <rptOwnerName>Luxor Capital Group, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1114 AVENUE OF THE AMERICAS</rptOwnerStreet1>
            <rptOwnerStreet2>29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001393021</rptOwnerCik>
            <rptOwnerName>Luxor Capital Partners, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1114 AVENUE OF THE AMERICAS</rptOwnerStreet1>
            <rptOwnerStreet2>29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001479129</rptOwnerCik>
            <rptOwnerName>Luxor Wavefront, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1114 AVENUE OF THE AMERICAS</rptOwnerStreet1>
            <rptOwnerStreet2>29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option to acquire 7% Convertible Notes due 2018</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>286650</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2013-09-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionTotalValue>
                    <value>286650</value>
                </transactionTotalValue>
                <transactionPricePerShare>
                    <value>1</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2013-09-18</value>
            </exerciseDate>
            <expirationDate>
                <value>2014-09-18</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>716625</value>
                    <footnoteId id="F2"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <valueOwnedFollowingTransaction>
                    <value>286650</value>
                </valueOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Option to acquire 7% Convertible Notes due 2018</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>93150</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2013-09-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionTotalValue>
                    <value>93150</value>
                </transactionTotalValue>
                <transactionPricePerShare>
                    <value>1</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2013-09-18</value>
            </exerciseDate>
            <expirationDate>
                <value>2014-09-18</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>232875</value>
                    <footnoteId id="F2"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <valueOwnedFollowingTransaction>
                    <value>93150</value>
                </valueOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Option to acquire 7% Convertible Notes due 2018</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>10200</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2013-09-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionTotalValue>
                    <value>10200</value>
                </transactionTotalValue>
                <transactionPricePerShare>
                    <value>1</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2013-09-18</value>
            </exerciseDate>
            <expirationDate>
                <value>2014-09-18</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>25500</value>
                    <footnoteId id="F2"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <valueOwnedFollowingTransaction>
                    <value>10200</value>
                </valueOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See</value>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Option acquired concurrently with purchase of 7% Convertible Notes due 2018 reported on Form 4 filed on September 20, 2013.</footnote>
        <footnote id="F2">Number of shares of common stock issuable upon conversion of the Convertible Notes, convertible at $0.40, issuable upon exercise of the Option.</footnote>
        <footnote id="F3">Reflects the Option to acquire Convertible Notes of the issuer owned directly by Luxor Capital Partners, LP (the &quot;Onshore Fund&quot;).</footnote>
        <footnote id="F4">Reflects the Option to acquire Convertible Notes of the issuer owned directly by Luxor Wavefront, LP (the &quot;Wavefront Fund&quot;).</footnote>
        <footnote id="F5">Reflects the Option to acquire Convertible Notes of the issuer held in accounts managed separately (the &quot;Separately Managed Accounts&quot;) by Luxor Capital Group, LP (&quot;Luxor Capital Group&quot;).</footnote>
        <footnote id="F6">Luxor Capital Group acts as the investment manager of the Onshore Fund, the Wavefront Fund (the &quot;Luxor Funds&quot;) and the Separately Managed Accounts.</footnote>
        <footnote id="F7">Luxor Management, LLC (&quot;Luxor Management&quot;) is the general partner of Luxor Capital Group.  Mr. Leone is the managing member of Luxor Management.  LCG Holdings, LLC (&quot;LCG Holdings&quot;) is the general partner of the Luxor Funds.</footnote>
        <footnote id="F8">Luxor Capital Group, Luxor Management and Mr. Leone may each be deemed to indirectly beneficially own the Convertible Notes held by the Luxor Funds and the Separately Managed Accounts.  LCG Holdings may be deemed to indirectly beneficially own the Convertible Notes held by the Luxor Funds.  For purposes of this Form 4, Luxor Capital Group, Luxor Management, LCG Holdings and Mr. Leone each disclaims beneficial ownership of the Convertible Notes owned by the Luxor Funds, except to the extent of their or his pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Norris Nissim, General Counsel of Luxor Management, LLC, as General Partner of LUXOR CAPITAL GROUP, LP</signatureName>
        <signatureDate>2013-09-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
