Diamond or Sand: a way to discrimination

Scientists have found some kind of carbon made particles on the planets which are thousand light years away from the earth. They reckon that there might be even diamond in abundance like sand on earth. Hearing this some might like to get some diamond from the planets if we can possibly travel these thousands of light years. I like the idea but I won't really like to go the planet to get some mere stones. I consider these diamonds or any other precious stones as mere stones. You might like to debate with me as to why I say this. Let me clarify the concept of precious and non-precious; if human get something in abundance, they consider it as non-precious taking for granted that this is available in plenty, example, Stones, sand, mud etc. But if human don't get something in plenty then it is precious, like diamond, gold, silver, platinum etc. 

I have a further clarification on the subject; who decides something precious or valuable then something else? It is we human come to a conclusion that something is not available so easily therefore it is valuable. Gold and Iron are two different kinds of metals but basically they are metals which are made from some elementary raw metals from the earth. But we are well aware that gold is not an ordinary metal since it can fetch loads of money and it is valuable metal whereas iron is cheap metal which is absolutely necessary for our human existence unlike gold only used for ornaments and decorations. Therefore we are the masters of ourselves. One fine day we all vote and decide that iron is more valuable than gold, gold is going to be cheaper than iron. 

Let me come to an important issue after discussing above metallic topic; do we humans have a right to decide which human is valuable or non-valuable in other words why there is discrimination in terms of caste, colour, creed, language, ethnicity, religion and so on? In yesteryears some powerful people decided the trade of the world and its system and others like sheep adhered to it. Do we have to continue doing that? We cannot simply say Yes. If we say yes what about the government, it is some government officials decide and we follow. Therefore, discrimination has been integral part of this world and human system. Just like the preciousness of the stones has been determined by some people, human system has been fashioned according to the wimps and fancies of some powerful brats. Do we have a way out of it? Well, we do since we are the master of ourselves, but this can have its impact sometime if not immediately. Thus we can bring change if we want. Drop make ocean therefore our hopes and aspiration should be aroused to enable us to march towards a world which will be free of discrimination of any sort.