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Document and Entity Information - shares
 3 Months Ended
Mar. 31, 2018
May 07, 2018
Document And Entity Information    
Entity Registrant Name GraniteShares Platinum Trust  
Entity Central Index Key 0001690842  
Document Type 10-Q  
Document Period End Date Mar. 31, 2018  
Amendment Flag false  
Current Fiscal Year End Date --06-30  
Entity Filer Category Smaller Reporting Company  
Entity Common Stock, Shares Outstanding   45,000
Trading Symbol PLTM  
Document Fiscal Period Focus Q1  
Document Fiscal Year Focus 2018