v3.26.1
Cover - USD ($)
 12 Months Ended
Jun. 30, 2026
Aug. 13, 2026
Cover [Abstract]    
Document Type 10-K  
Amendment Flag false  
Document Annual Report true  
Document Transition Report false  
Document Period End Date Jun. 30, 2026  
Document Fiscal Period Focus FY  
Document Fiscal Year Focus 2026  
Current Fiscal Year End Date --06-30  
Entity File Number 001-38349  
Entity Registrant Name GRANITESHARES PLATINUM TRUST  
Entity Central Index Key 0001690842  
Entity Tax Identification Number 82-6644954  
Entity Incorporation, State or Country Code NY  
Entity Address, Address Line One c/o GRANITESHARES LLC  
Entity Address, Address Line Two 250 Broadway – 24th floor  
Entity Address, City or Town New York  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10007  
City Area Code (646)  
Local Phone Number 876 5096  
Title of 12(b) Security GraniteShares Platinum Shares  
No Trading Symbol Flag true  
Security Exchange Name NYSEArca  
Entity Well-known Seasoned Issuer No  
Entity Voluntary Filers No  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Public Float $ 162,846,000  
Entity Common Stock, Shares Outstanding   10,900,000
Documents Incorporated by Reference [Text Block] None  
Document Financial Statement Error Correction [Flag] false  
Auditor Firm ID 445  
Auditor Opinion [Text Block] We have audited the accompanying statements of assets and liabilities of GraniteShares Platinum Trust (the “Trust”), including the schedules of investments, as of June 30, 2026 and 2025, the related statements of operations, the statements of changes in net assets, and the financial highlights for each of the years in the three-year period ended June 30, 2026, and the related notes (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Trust as of June 30, 2026 and 2025, and the results of its operations, the changes in its net assets, and the financial highlights for each of the years in the three-year period ended June 30, 2026, in conformity with U.S. generally accepted accounting principles.  
Auditor Name TAIT, WELLER & BAKER LLP  
Auditor Location Philadelphia, Pennsylvania