What invoicing format must a numismatic dealer use to issue a legally valid GST invoice for the sale of a currency note or coin?

The mandatory elements of a valid GST tax invoice

Rule 46 of the CGST Rules 2017 prescribes 16 mandatory elements for a tax invoice. For a numismatic dealer, the critical elements are: the name, address, and GSTIN of the registered dealer (supplier); a consecutive serial number for the invoice; the invoice date; the buyer's name, address, and GSTIN (if the buyer is a registered person); the HSN code for each item sold; a description of the goods (denomination, series, serial number prefix, approximate condition); the quantity; the total value of supply; the taxable value; the applicable GST rate (clearly stating whether it is 5% or 12%); the GST amount — CGST and SGST split for intra-state, IGST for inter-state; and a digital or physical signature.

The description requirement — what 'description of goods' means for numismatics

For standard manufactured goods, the description field is straightforward — 'Steel chair, model XYZ, quantity 4.' For numismatic notes, the description must adequately identify the specific item sold. A description of 'Indian currency note' is legally insufficient. A description should include: denomination (e.g., ₹100); series (e.g., Mahatma Gandhi Series); prefix (e.g., prefix 2A); condition (e.g., UNC/Uncirculated); and any special characteristics (e.g., star note, error note with missing serial number).

For a buyer who may later need to prove they acquired a specific item, the invoice description is documentary evidence. A vague description — 'old currency note, ₹2,500' — provides minimal protection in any dispute. A precise description — '₹100 Mahatma Gandhi Series, prefix 2A, UNC condition, star note, serial number ★2A 123456' — is both GST-compliant and commercially protective for both parties.

The HSN code — coins and notes get different codes

The HSN code is a mandatory element and the element most commonly omitted or incorrectly applied by numismatic dealers. Coins and notes attract different HSN codes and different GST rates. Numismatic coins: HSN 9705, 5% GST. Numismatic banknotes and historical paper currency: HSN 4907, 12% GST. Framing or mounting services: SAC 999, 18% GST.

An invoice that applies HSN 9705 and 5% to a banknote sale — because the dealer used their coin HSN for everything — is a defective invoice. The buyer cannot claim ITC at 5% if the correct rate was 12%. Both parties face compliance exposure.

Invoice number series and record keeping

GST invoices must be numbered in a consecutive series within each financial year. The numbering must restart at the beginning of each financial year. A dealer must maintain copies of all issued invoices. Invoices must be available for inspection by GST authorities and must be retained for at least 72 months (6 years) from the due date of the relevant annual return.

Laws & authorities referenced in this chapter

CGST Rules 2017 — Rule 46 (mandatory elements of tax invoice — 16 prescribed elements)

CGST Act 2017 — §31 (obligation to issue tax invoice for every supply)

HSN 9705 — numismatic coins (5%); HSN 4907 — numismatic notes (12%); SAC 999 — services (18%)

CGST Act 2017 — §35 (record keeping; 72-month retention period)