A cross trade (or cross-tier trade) is when one of the goods if from one tier and the other is from another tier. So, marble, steel, or planks for crystal, scrolls, silk, elixir, dust, or gems would be a cross-tier trade. The way Inno adjusted the trade ratios brought the cross-tier trades closer to true cost of the goods. They were 1 : 4 : 16. The current ratios of 1 : 1.5 : 2.25 are much closer to actual cost producing the goods. However, there are very strong opinions about cross-tier trades and about the use of the word 'fair'. In the game, Inno refers to 'fair' as 2-star trades.