What investment type does form 8949 fit into when amending my submitted taxes(refund received) to report purchases/sales of gold coins(here-to-for unreported)?

Form 8949 is used for a variety of investment types to reconcile amounts that were reported to you and the IRS on Form 1099-B or 1099-S (or substitute statement) with the amounts you report on your return. The subtotals from this form will then be carried over to Schedule D (Form 1040), where gain or loss will be calculated.

In order to enter information regarding the sale of gold held for investment in TurboTax Online:

• Go to Wages and Income
• Select Investments and Savings
• Click +Add Investment
• Select a financial institution for import, or click Enter a Different Way
• Select Other for Investment Type
• When asked to identify the type of investment from a drop-down list, select Collectible
• Fill in the information about the purchase and sale in the fields provided

TurboTax will calculate any gain and transfer the information to the correct tax forms.

See IRS Publication 550 for more information on the taxation of investments.

gold coins would be a collectible so that would need to be coded C (Column f of form 8949).   collectibles can be taxed at a higher rate than a gain on the sale of stock.