Flux Process

 

Solution-Growth Processes

Flux Process

Chatham (red, orange, blue), Kashan (red), Ramaura (red), Knischka (red), Lechleitner (overgrowths in various colours), Novosibirsk (red), Douros (red).

1.   Primary flux-filled negative crystals, often only partially filled (two- phase) and featuring a characteristic crazed surface appearance. Primary flux in Ramaura stones often has a yellow-orange colour

 

and may show distinct growth striation on flux surfaces, open cavi- ties and crystal faces which mirror the colour zoning.

2.   Secondary flux-filled fingerprints, feathers, etc.

3.   Tiny flux particles, often arranged in streamer or comet-like patterns (such as ‘rain’ in Kashan stones).

4.   Platinum plates, flakes, crystals, needles, etc. (Chatham, Knischka); black (platinum-rich?) growth planes (Chatham only, especially along the seed crystal).

5.   Very small, oriented, exsolved silk-like needles and/or particles in zoned clouds (Chatham and Knischka).

6.   Polysynthetic and growth twinning in various orientations, but with- out the boehmite needles often present in the natural, Verneuil and Seiko (floating zone) synthetics.

7.   Straight growth lines running parallel to crystal faces and meeting at 11 specific angles. Unusual growth-line boundaries (Ramaura, Douros [Greece]).

8.   Chatham: rounded transparent crystals of low relief (possibly chrysoberyl).

9.   Seed crystal, generally with trapped flux on the boundary. The boundary may be difficult to see in the Lechleitner overgrowth.

10.   Knischka: primary negative crystals which often display a two-phase filling. These may be bipyramidal or irregular in shape and some- times are surrounded by irregular bluish white clouds.