It is a personal asset. A collectible might be an investment. other than stocks, that you hope will increase in value.
Collectibles under IRC Section 408(m)(2) include:
Any work of art,
Any rug or antique,
Any metal or gem (with limited exceptions, below),
Any stamp or coin (with limited exceptions, below)
Any alcoholic beverage, or
Any other tangible personal property that the IRS determines is a "collectible" under IRC Section 408(m).
Prohibited transactions
Acquiring a collectible may also be a prohibited transaction under IRC Section 4975(c). For example, the purchase of a collectible with plan funds for the personal use of a disqualified person could be a prohibited transaction under IRC Section 4975(c)(1)(D). An example could be the acquisition of artwork or rugs by an individually-directed account for use in the participant’s own home.