Exchanging Rares - A mechanic to harmonise rare prices

Look at the amounts up for sale. On AB there are both 5 pages of Silicate Loams and Incarnidine Clusters. People buy up any loam onder 4 plat as soon as it shows up... why you ask? Look at the prices of Adept scout and fighter spells. There are a few creating an artificial cap. If they are being bought for 4 plat no one is going to drop them under 4 plat even though there were actually more Loams then Incarnadine when I last checked. Incarnadine is going for about 20 gold. Any cheaper and I will buy and transmute...
I buy any gems that drop under 1.5 plat make the Adept then make the potions from the dusts which sell for about 60 gold then transmute the Adept which makes powder. With that I make an Adornment that goes for roughly 1.5 plat ... I make about 50+ gold per shot sometimes more.