Costco now sells platinum bars. Here's what you should know, from price to availability.

Costco is expanding its offering of precious metals, building on its frequent introduction of gold bars last year sold out within a few hours. The retailer is now expanding its range to include 1-ounce platinum bars.

The new bar is described as 999.5 pure platinum and will be made in Switzerland by a refiner who has achieved Good Delivery accreditation from the London Bullion Market Association (LBMA), an international trade association for the precious metals industry.

Costco's gold bars were so popular with customers that the retailer had difficulty keeping them in stock. After the retailer added silver coins to its lineup, Wells Fargo estimated that the chain sold that much 200 million dollars in gold and silver every month to its members.

How much is Costco platinum bar?

The platinum bar costs $1,089.99 – if you can get it.

The bar is only sold online and Costco says delivery is not available in Nevada, Louisiana and Puerto Rico. However, the Costco website also noted Thursday that the platinum bar was out of stock in several other locations in the U.S., including New York and Utah.

Costco did not immediately respond to a request for comment.

Is there a purchase limit?

Yes, Costco says it limits members to one purchase, with a maximum of five platinum bars per transaction.

Is platinum a good investment?

The precious metal, used in both jewelry and industrial goods such as catalysts, has not performed as well recently as gold, which has long been viewed by investors as both a hedge against inflation and a source of financial stability when stocks – and bond markets are volatile.

Over the past year, the spot price of platinum has risen about 16%, compared with a 42% increase for gold, FactSet data shows.

According to financial services firm FactSet, the current spot price for platinum is $1,004 per ounce, meaning Costco's price is about 8% above market value.