Why are some of potions in the shop sparkling?

Some of the potions that can be bought from the shop now have a kind of sparkling, glittering animation to them. For example, see the two leftmost potions in this picture:

I read the release notes of the Watcher DLC; it mentions that several potions now have new icons.

Is this a purely cosmetic change, or do the sparkles affect gameplay?

Solution 1:

You may have observed a tendency for sparkling potions to be more expensive.

The sparkles indicate the rarity of the potion. The Forge potion, which is common, does not sparkle, while the Gambler's Brew and the Distilled Chaos are both uncommon show a few moderately bright sparkles.

If there would be a rare potion for sale, like for example a Cultist potion or Entropic Brew, those would have lots of even brighter sparkles.

A potion in a shop has a 65% (about 2 in 3) chance of being common, 25% (or 1 in 4) of being uncommon, and 10% (or 1 in 10) chance of being rare.