Rose Egg 624a-96 by Bob Keller

Rose Egg 624a-96 - designed by Bob Keller ©2014
624 facets96 index
L/W = 1.000 H/W = 1.167Vol./W^3 = 0.593

Hemisphere A (Spherical)
P90.00°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Make cylindrical preform, set size
182.56°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Match P, make level girdle
278.95°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet P.1
370.92°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet 1.2
467.67°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Meet 1.2.3
552.74°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Meet 3.4
650.45°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet 3.4.5
739.17°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet 5.6
837.74°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Meet 5.6.7
922.67°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Meet 7.8
1022.14°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet 7.8.9
117.63°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet 9.10, apex
Hemisphere B (Ellipsoid)
a85.81°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Match 1 on Hemisphere A
b82.14°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet 1.a
c80.87°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet a.b
d77.29°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Meet a.b.c
e68.33°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Meet c.d
f65.20°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet c.d.e
g61.39°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet e.f
h58.61°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Meet e.f.g
i47.82°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Meet g.h
j45.84°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet g.h.i
k37.01°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet i.j
l35.71°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Meet i.j.k
m22.19°02-06-10-14-18-22-26-30-34-38-42-46-50-54-58-62-66-70-74-78-82-86-90-94Meet k.l
n21.67°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet k.l.m
o7.61°96-04-08-12-16-20-24-28-32-36-40-44-48-52-56-60-64-68-72-76-80-84-88-92Meet m.n, apex

Download PDF format printer friendly cutting instructions: [ Download Icon Rose Egg 624a-96 Printer Icon ]

Download the GemCad format design file: [ Download Icon rose_egg_624a-96.gem ]

Rose Egg 624a-96 Cutting Notes

Rose Egg 624a-96 was designed for a large glass, exhibition size egg. Of course a piece of natural rough the size of your fist is also suitable if you happen to have one laying about... Experienced faceters who appreciate the challenge of elaborated projects and enjoy showing off their work may find this egg suitable.

This is actually a simple design to cut in terms of its symmetry and indexing, there being only two sequences of equally spaced indexes, (96-04-08...84-88-92 and 02-06-10...86-90-94) alternately employed on 26 courses of 24 facets each. That's 624 facets, which is a fair amount of facets to cut and polish. However, the cutting and polishing goes faster on projects like this than one might think, due to the high symmetry and large number of facets dividing the surface area into 624 relatively small projects.

It's easy to get lost among 624 facets, so keep careful track of where you are in the diagram sequences. I find it helps to keep my place by marking off each elevation angle change at the start of each course, and each index change as the facets in a course are cut. Verify thrice, cut once...

Most faceting machines are capable of cutting larger stones than can be dopped with normal size transfer fixtures. If your ambition is larger than your fixture, consider employing a drill press as an alignment aid for dopping and transferring large stones.

The apex (pole) facets are rather shallow (7.63° on Hemisphere A and 7.61° on Hemisphere B) and may be challenging to cut on some machines. If you haven't previously cut facets this shallow on your machine, rehearsing a test course of these before committing to the project may save you some frustration and anguish.

Begin by cutting a 24-sided cylindrical preform. The height of the preformed cylinder must be equal to or greater than 1.167 times its width for you to have enough material when you get to the course 11 and o (pole) facets. When you cut the course 1 facets for the A hemisphere, create a level 'girdle' (equator) line dividing the height of cylinder proportionately, allowing 1.33 times more for the z dimension of the B hemisphere as the A hemisphere.

Transfer when you've finished the A hemisphere, and cut the course a-o sequence on the B hemisphere.

If you cut a Rose Egg 624a-96 of your own, be sure and let me know what you've cut and how you made out.


Index of Gem Designs

Perfect Transfer Index

Table of Contents

Bob Keller