Apex Pinwheel

Faceting Diagram Search:
Shape:
L/W Min: Max:
Gear:
RI Min: Max:
Facets Min: Max:
 


Apex Pinwheel



Apex Pinwheel – designed by Richard Anderson rlbjanderson@mcn.net
Originally published in FACETS April 1996
Angles for R.I. = 1.54 72 facets + 16 facets on girdle = 88
8-fold, mirror image symmetry 96 index
L/W = 1.000 P/W = 0.466 C/W = 0.210 H/W = (P+C)/W+0.02 = 0.696 P/H = 0.670 C/H = 0.301
Vol./W^3 = 0.220 Brightness at 0 degrees tilt for quartz COS = 44.8 ISO = 48.6

Pavilion
pb 44.40 03-09-15-21-27-33-39-45-51-57-63-69-75-81-87-93 Pavilion breaks – cut to center point
g 90.00 03-09-15-21-27-33-39-45-51-57-63-69-75-81-87-93 Girdle – cut to meet pb
pm 43.00 96-12-24-36-48-60-72-84 Pavilion mains – cut to meet g,pb and at cutlet
Crown
1 43.50 03-09-15-21-27-33-39-45-51-57-63-69-75-81-87-93 Crown breaks – cut to meet g, make level upper girdle line
2 37.00 96-12-24-36-48-60-72-84 Crown mains – cut to meet g,1
3 22.00 06-18-30-42-54-66-78-90 Crown stars – cut to meet 1,2
4 14.00 96-12-24-36-48-60-72-84 Crown high stars – cut to meet 2,3
5 8.00 96-12-24-36-48-60-72-84 Apex pinwheel – cut to meet 3,4
For topaz etc. use 43° mains and 44.4° breaks. For sapphire etc. use 41° mains and 42.3° breaks.

Recently, I finished a new cut of a round brilliant. Is this new – or just new to me? I have no idea. It was new to me! I have been faceting for several years and have developed a desire to cut as close to perfection as my eyes and my machinery will allow.

To preform my Apex Brilliant crown, start with as well cut standard pavilion as possible using a 96 gear.

Begin with the Break facets, Mains, Stars, High Stars and Apex Pinwheel. Cut and polish in this order.

This cut must be accurate or the apex will appear off center. The Apex Brilliant is intended for material that is light to medium color intensity. I have enjoyed greatly improved flash as a result of this crown. I hope you will also enjoy trying it.