Chapter 14: Artificial, Synthetic and Imitation Gem Materials

These flashcards cover the key concepts, definitions, and identification features of various artificial, synthetic, and imitation gem materials as outlined in Chapter 14.

What are the main differences between natural, artificial, and synthetic gem materials?

Natural materials are formed by natural processes without human interference. Artificial materials are manufactured from natural or artificial components, while synthetic materials have a natural counterpart with the same composition and properties.

What are examples of synthetic materials produced using the Verneuil flame fusion method?

Synthetic corundum, synthetic star corundum, and synthetic spinel.

What is the flux method used for in gem synthesis?

The flux method is used to grow synthetic emeralds, synthetic spinel, and other beryls by dissolving ingredients in molten flux at high temperatures.

What distinguishes composite materials from natural stones?

Composite materials are artificially assembled from two or more components, giving the impression of a single stone, while natural stones are formed naturally.

Define imitation material in the context of gemstones.

An imitation material is a natural or artificial material that imitates the appearance of gemstones without possessing their chemical and physical properties.

What method is used for high-pressure synthesizing of diamonds?

The High-Pressure High-Temperature (HPHT) method mimics natural diamond formation.

What color and appearance indicators can be found in synthetic star corundum compared to natural star corundum?

Synthetic star corundum has vivid color and a well-defined, centered star, whereas natural star corundum has less saturated color and a less defined star.

How can one identify flux-grown synthetic emerald?

By observing flux feathers, flux-filled cavities, and metal inclusions from the crucible.

What are the two main methods of producing synthetic diamonds?

High-pressure high-temperature (HPHT) synthesis and chemical vapor deposition (CVD) synthesis.

What is the identification feature unique to synthetic moissanite?

Synthetic moissanite exhibits strong double refraction and high dispersion, significantly higher than diamond.

How can pressed materials be described in relation to their production?

Pressed materials are formed by bonding or fusing small fragments of gem material to create larger composite pieces.

What identifying features can be typically observed in artificial glass?

Common identifying features include bubbles, swirls, and specific refractive index values.

What is the unique structure of 'synthetic' opal when compared to natural opal?

'Synthetic' opals have a columnar structure and complete coverage of iridescence, which is rarely seen in natural opals.

What distinguishes corundum doublets from natural corundum?

Corundum doublets are made by gluing a thin crown of natural sapphire to a pavilion of synthetic corundum, exhibiting unnatural proportions and limited natural features.

What method is used to identify soudé-type composites?

Observing a straight junction line at the girdle and noting the different RI readings for the crown and pavilion.