Up to this point we have considered men in only one economic capacity,
 that of owners of commodities, a capacity in which they appropriate the
 produce of the labour of others, by alienating that of their own labour.
 Hence, for one commodity-owner to meet with another who has money, it is
 necessary, either, that the product of the labour of the latter person,
 the buyer, should be in itself money, should be gold, the material of which
 money consists, or that his product should already have changed its skin
 and have stripped off its original form of a useful object. In order that
 it may play the part of money, gold must of course enter the market at
 some point or other. This point is to be found at the source of production
 of the metal, at which place gold is bartered, as the immediate product
 of labour, for some other product of equal value. From that moment it always
 represents the realised price of some commodity. [19]
 Apart from its exchange for other commodities at the source of its production,
 gold, in whose-so-ever hands it may be, is the transformed shape of some
 commodity alienated by its owner; it is the product of a sale or of the
 first metamorphosis C—M. [20] Gold, as we saw, became
 ideal money, or a measure of values, in consequence of all commodities
 measuring their values by it, and thus contrasting it ideally with their
 natural shape as useful objects, and making it the shape of their value.
 It became real money, by the general alienation of commodities, by actually
 changing places with their natural forms as useful objects, and thus becoming
 in reality the embodiment of their values. When they assume this money-shape,
 commodities strip off every trace of their natural use-value, and of the
 particular kind of labour to which they owe their creation, in order to
 transform themselves into the uniform, socially recognised incarnation
 of homogeneous human labour. We cannot tell from the mere look of a piece
 of money, for what particular commodity it has been exchanged. Under their
 money-form all commodities look alike. Hence, money may be dirt, although
 dirt is not money. We will assume that the two gold pieces, in consideration
 of which our weaver has parted with his linen, are the metamorphosed shape
 of a quarter of wheat. The sale of the linen, C—M, is at the same time
 its purchase, M—C. But the sale is the first act of a process that ends
 with a transaction of an opposite nature, namely, the purchase of a Bible;
 the purchase of the linen, on the other hand, ends a movement that began
 with a transaction of an opposite nature, namely, with the sale of the
 wheat. C—M (linen—money), which is the first phase of C—M—C (linen—money—Bible),
 is also M—C (money—linen), the last phase of another movement C—M—C
 (wheat—money—linen). The first metamorphosis of one commodity, its
 transformation from a commodity into money, is therefore also invariably
 the second metamorphosis of some other commodity, the retransformation
 of the latter from money into a commodity. [21]