The CVV Number ( C ard V erification V alue) on your credit card or debit card is a 3 digit number on VISAÂ®, MasterCardÂ® and DiscoverÂ® branded credit and debit cards. On your American ExpressÂ® branded credit or debit card it is a 4 digit numeric code.
1 Diamonds are formed deep within the Earth: between 100 km and 200 km below the surface. 2  The temperatures are about 900 - 1300 C in the part of the Earth's mantle where diamonds form. 3  The pressure is between 45 - 60 kilobars.
Graphite and diamond are the two mineral forms of carbon. Diamond forms in the mantle under extreme heat and pressure. Most graphite found near Earth's surface was formed within the crust at lower temperatures and pressures. Graphite and diamond share the same composition but have very different structures.