It's just another type of goods to produce in your factories. When factories are raised beyond level 23 (Starting around the elementals chapter) they lose the ability to queue 24 and 48 hour productions, and instead offer two new slots of sentient goods. For every existing good, there is a sentient match. Marble becomes Moonstone, Steel becomes Platinum, and Planks become Elven Tree Gum. A significant difference is that like mana and seeds, they decay overnight, with 10% of what you hold turning back into the earlier good from which it was made. They are soemtimes referred to as T4, T5, And T6 goods.
Your boosted sentient goods are based on a different set of relics than the originals, which are often referred to as "Boost plus one" or "B+1" which I
talked about here recently.