Star Cut by Torbjörn Lorin

Star Cut - designed by Torbjörn Lorin torbjorn.lorin@telia.com
Angles for R.I. = 1.55 49 facets + 8 facets on girdle = 57
4-fold, mirror image symmetry 96 index
L/W = 1.000 T/W = 0.387 T/L = 0.387 P/W = 0.462 C/W = 0.176 H/W = (P+C)/W+0.02 = 0.659 P/H = 0.702 C/H = 0.268
Vol./W^3 = 0.201 Brightness at 0 degrees tilt for quartz
COS = 52.9 ISO = 61.3

Pavilion
90.00 06-18-30-42-54-66-78-90 Cut girdle to a symmetrical 8-sided shape
1 52.00 06-18-30-42-54-66-78-90 Level girdle
2 48.00 05-19-29-43-53-67-77-91 Meet 1 and corner
3 43.00 02-22-26-46-50-70-74-94 Meet 2 in corner
Crown
a 42.00 06-18-30-42-54-66-78-90 Level girle height
b 36.00 05-19-29-43-53-67-77-91 Meet a in corner
c 30.00 01-23-25-47-49-71-73-95 Meet b in corner
0.00 Table Meet b

Star Cut - Cutting Instructions

You can first cut a conical preform at angle 43.00, with symmetrical 8-sided facets with the same index values as the girdle facets. You can cut in the order as given in the table above, or you could also start cutting on pavilion facet 3 and cut to a culet meetpoint. Then cut the girdle facets to establish the stone's width. After that, you can cut facets 1 and 2 to meet in the corners. BE CAREFUL as the facets are sharp pointed, and cut very quickly to the corners.

One of the most important things is to get the facets as flat as possible when they are finished. Do not use too soft a polishing lap. Rounded facets and rounded edges give a poorer brilliance. Polishing on Ultra Laps on a hard lap is OK. If you polish on a tin lap with alumina you will get a flatter surface, but you might have problems with scratces. Use your loupe frequently when you cut and polish your stone, and be sure you cut with your finer laps until all the scratches from the preceeding coarser lap are gone. If you don´t, it takes an extremely long time to polish in the end.

This cut is best suited for colorless or light colored materials. It is truly beautiful with absolutely colorless and waterclear materials. Quartz crystal is very appropriate and maybe materials with higher refractive indexes (I haven´t tried). I think it´s not so good with dark materials, so it is better to start with a piece of colorless quartz. It is cheap and you will not be disappointed. The example stone pictured above was cut from clear quartz.

The outline is symmetrical 8-sided, but the finished stone looks more square shaped. Take your finished stone and look at it outdoors on a cloudy day. I think you will enjoy it. Be sure you have cleaned the stone of any finger prints. Finger prints are disasterous for the brilliance.

The Star Cut was my first design and I cut it as my second stone. Now I have cut around 240 stones. I started faceting in 1987 when I bought a Raytech Shaw faceter.

Good luck with your Star Cut! - Torbjorn


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