Identification of Rough Crystals

1-   Two Thing Are IMPORTANT For The Identification Of Crystals.

• Shape & Symmetry.
• Surface Features.

-----------------------------------------------------------------------------

2- Fold Symmetry   DIAMOND RHOBUS

3- Fold Symmetry  TRIANGLE

4- Fold Symmetry  SQUARE

5- Fold Symmetry  RECTANGLE

Internal Observation With Loupe

 Solid :

• Crystal
• Neddles
• Fiber

Liquid:

• Fingerprints.
• Undefined Shape can also be .
• if there is water , the surface will shine .

Gass:

• Bubbles , black rim around the bubble      <---- (glass)
• Donut Bubble

Note: If It Is Natural ,it can also be round   ....Naturally , there will be TadPad shape bubbles....

sd

What is External Observation in Gemology?

 External   Observation

  Rough:-

1. Horizontal  Striations 
2. Vertical  Striations
3. Trigons  Striations
4. Etch Pits 
5. Pits
6. Terrace Like Mark
7. Cavity
8. Material Emeded in cavity
9. Facture

Cut & Polish

1. Scratch
2. Polishig Lines
3. Abraded facet Edges
4. Chipping
5. Cleavage
6. Facture

What Is Dichcroscope?

 

The dichroscope is an important pocket instrument used in the field of geology, and can be used to test transparent gemstones (crystals). Experienced geologists using pleochroism can successfully detect gemstones from other artificial stones using this instrument.

Calcite dichroscope

There are two types of dichroscopes available: calcite and polarizing. Of the two, calcite gives better results and is widely used by experienced gemologists. With the polarizing type, only one pleochroic color can be seen at a time. This makes the process time-consuming and difficult, though it is the most economical way to get results.

The dichroscope has been used since at least the start of the nineteenth century