I've just bought this moisturiser from SpaceNK, having finished my SPF 30 day cream from another brand.
Algenist is formulated with a proprietary ingredient, alguronic acid. This ingredient is derived from algae and is a polysaccharide like hyaluronic acid, but a more complex compound. More details can be found on www.algenist.com.
I obviously can't review this yet (I've only been using it for a few days) but I thought it might be helpful to post an ingredients list for anyone interested in it. The texture is a gel-cream, and feels plumping and hydrating without feeling greasy.
It is expensive at £68, but it is a 60ml size rather than 50ml or 30ml.