Obsidian was also an important trade good for Native Americans. Another main inter-Martian trade good during early colonization could be manure. Tyrian purple dye was an important trade good in the ancient Mediterranean. For example, one trade good mentioned is ""lakkos chromatinos"". He opened trade good stores in Carson City and Silver City. Each trade good is worth 15 points, and each Astro is worth 1. By 1787, trade good production had declined such that there remained only eight trade guilds.