NEW YORK — Take Amazon Prime, mix it with Pinterest and add a dash of Instagram. The result is Amazon Spark , a new shopping-focused “social network” aimed at getting hardcore Amazon users to spend even more money with the e-commerce giant.

The service launched publicly on Tuesday on Amazon’s iPhone app, although it’s already chock full of posts, so the company has clearly been testing it for a while. It’s only available to Prime members, who pay $99 a year for free shipping, streaming videos and other perks. An Android version is planned.

Like Pinterest, Spark lets users share photo-heavy posts about their interests, ideally those leading to shopping. “It’s to learn more, to sell more and to connect to customers,” said Bob Hetu, research director for retail at Gartner.

He noted that it’s not intuitive to find Spark on the Amazon app, suggesting that the company is not pushing it hard – at least not yet.

To use it, go to the “programs and features” section on the app’s menu bar. The tool will first ask you to select at least five interests. Once you do, you’ll see an Instagram-like feed of photo posts bearing shopping-bag icons that enumerate how many pictured items – plus related products – you can buy on Amazon.

A cursory glance on Wednesday showed polished-looking photos of travel scenes, cosmetics and kitchen gadgets for the interests “travel,” “food” and “beauty & grooming.” A user named Kassandra posted a stylized photo of a hand holding a bottle of bright red nail polish. Clicking on the photo highlights yellow dots on the purchasable items – and one tap will take you to an Amazon product page. In this case, the Smith & Cult nail polish was available for $18.

Spark has drawn comparisons to both Pinterest and Instagram, but it’s unclear if it will be a threat to either. Tech companies like Amazon, however, appear increasingly fond of cloning popular apps from fast-growing startups.