Diamond vs. Zircon: How to Identify Diamonds & Natural Pearls

Question
how to recognise diamonds from zircones?
how to recognise  natural pearls?

Answer
Dear gnei,

We use a 10X magnifier (loupe) to examine the "facet junctions" of a stone. Since a diamond is so hard and the facets are cut (not molded), the junctions look crisp and sharp. On CZ they are rounded. We also use a thermal diamond tester. In short, it takes an expert to know for certain.

When you say "natural" pearls do you mean telling cultured pearls from an imitation?. If so, try rubbing the pearl against the bottom of your front teeth. Cultured pearls feel a bit "rough" while imitations feel smooth and glassy.  

Rich