Squareburst Faceting Diagram: Precision Gem Cutting Design by A.Collins

Designed by A.Collins VFG (March 2021) with help from Michael (@breakfacets), Squareburst is a brilliant round faceting design crafted for high-refractive-index gemstones.

Optimized for materials with R.I. = 1.760 and above (such as Topaz, Sapphire, Ruby, and Spinel), this design features an intricate 4-fold mirror-image symmetry that creates a unique square starburst pattern inside a round outline.

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Design Specifications

Parameter	Specification Details
Design Name	Squareburst
Author	A.Collins VFG (March 2021)
Target RI Range	R.I. = 1.760 (Suitable for Topaz, Sapphire, Ruby & Higher)
Facet Count	49 + 16 girdles = 65 total facets
Symmetry / Index	4-fold, mirror-image symmetry | 96 Index Gear
Proportions	L/W=1.000 | T/W=0.300 | U/W=0.300 P/W=0.457 | C/W=0.169
Volume Ratio	Vol./W³ = 0.211

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Step-by-Step Cutting Angles

1. Pavilion Cutting Sequence

Facet	Angle	96-Index Settings	Instruction / Meet Point
P1	45.00°	96-12-24-36-48-60-72-84	TCP (To Cut Point)
G1	90.00°	03-09-15-21-27-33-39-45-51-57-63-69-75-81-87-93	Meet P1
P2	40.00°	05-07-17-19-29-31-41-43-53-55-65-67-77-79-89-91	Meet P1, G1

2. Crown Cutting Sequence

Facet	Angle	96-Index Settings	Instruction / Meet Point
C1	50.00°	06-18-30-42-54-66-78-90	Level Girdles
C2	29.20°	96-12-24-36-48-60-72-84	Meet G1, C1
C3	17.80°	12-36-60-84	Meet C1, C2
C4	13.00°	96-24-48-72	Meet C1, C2, C3
T	0.00°	Table	Table

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Suitable Gemstone Materials

Designed specifically for gemstones with high RI values (1.76 and above):

• Corundum (RI 1.76 - 1.77): Ruby & Sapphire—delivers maximum brilliance and deep color contrast.
• Spinel & Garnet (RI 1.72 - 1.81): Creates a striking geometric starburst pattern across the table.
• Topaz (RI 1.61+): Functions well, though best brightness is achieved on higher RI roughs.

Explore more custom faceting diagrams and precision lapidary guides on Horizon Gems!