​Machtoub Jewelry

MACHTOUB  JEWELRY

Banknote collecting, or Notaphily, is a slowly growing area of numismatics. Although generally not as widespread as coin and stamp collecting, the hobby is slowly expanding. Prior to the 1990s, currency collecting was a relatively small adjunct to coin collecting, but the practice of currency auctions, combined with larger public awareness of paper money, has caused more interest in and valuation of rare banknotes.[citation needed]

Since 2007 Sanjay Relan, of Hong Kong, has held the Guinness world record for collecting 221 banknotes representing 221 different countries. For a short period in 2007, he also held the Guinness world record for collecting 235 coins representing 235 different countries.

In mineralogy, diamond (/daɪ(ə)mənd/; from the ancient Greek ἀδάμας – adámas "unbreakable") is a metastable allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at standard conditions. Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material. Those properties determine the major industrial application of diamond in cutting and polishing tools and the scientific applications in diamond knives and diamond anvil cells.