What is the difference between a white truffle and a black Summer truffle?

Many people are confused about the difference in quality between a white truffle and a Summer truffle. The following should give you some idea of the difference:

Here in Piemonte, 2008 white truffles are selling for about 4.5- 6.5 Euros per gram depending on size and quality.

Piemonte summer truffles can be bought locally for about .13 euros a gram (in fact, I can buy them from a neighbor for 5 Euros for 100 grams) so the difference in price locally between an Italian (even Piemontese) summer truffle and a proper white truffle is 4.57 Euros a gram or 4,570 Euros a kilo.

Roughly 40 times the price.