As Heinrich states, "Value does not arise somewhere to then be 'there'." Value is not a thing but rather a social relationship. It emerges neither through production nor through exchange, but presupposes both. It is a property something is assigned in relation to other things, which then gives the appearance of possessing it quite apart from such a relationship. As Marx insists on repeatedly, value is a ghostly or over-sensual property, not a substantial one. The conception of a commodity possessing its value objectivity independent of these relations is a semblance that transforms a social property into what is taken to be a natural one.
The same situation applies to Pierre Bourdieu's non-economic concept of capital. One must both work for one's capital, get an education, practice, and produce something which is recognised by the field of science or art in order to become a scientist or an artist, or else one becomes neither, regardless of what one has produced for the drawer or the hard disc. Similarly, the value-relation does not arise in exchange without a labour process, but without exchange, concrete labour would never be reduced to abstract labour either, and thus, no value would emerge. One might also bring to mind Ludwig Wittgenstein's by now famous, and to modern social sciences so significant statement, that one cannot have a private language. The same thing applies to the value, one cannot decide it on one's own.
from Eurozine article by Anders Ramsay about Marx's theory of value. Emphasis added. Value is a complex, condensed relation, not a transferable property. Its abstraction is always ideological, since it depends entirely on its specific embeddedness. It is a quality and never a quantity.