Faceting an Exceptional Arizona Peridot
Arizona peridot is a staple of Southwestern lapidary, but finding rough material of exceptional scale is a rare treat. When my dad handed me a parcel of rough peridot, the sheer size of the pieces immediately stood out. After faceting the largest gem from the batch as a custom gift for him, I was thrilled to bring this second gem-grade giant to the lap. This finished piece is now available in the online shop Here , but the journey on the machine had its own unique nuances worth diving into.
Designing for Depth & Light Return
Large peridot rough requires careful orientation and precision angle selection to preserve yield without sacrificing brilliance or depth of color. To maximize the material's optical characteristics, I roughed in a round outline and mapped out a modified Standard Round Brilliant (SRB) design. Customizing the pavilion and crown angles specifically for this stone’s refractive index ensured full light return while preventing windowing across the broad table.
Workshop Workflow & Lap Sequence
Working through the faceting sequence required a deliberate shift from standard prep-polish protocol:
Roughing & Pre-Forming: 250 grit and 500 grit diamond laps to establish the girdle radius, rough in the cone, and map out primary facet junctions.
Pre-Polish Adjustment (8k Diamond): Peridot is notorious for developing "orange peel" texture—micro-rippling along specific crystal orientations—when using standard 3k pre-polish laps. While altering lap rotation direction can sometimes mitigate this friction heat and surface drag, skipping 3k entirely and jumping straight to 8k provides a much smoother, risk-free transition.
Final Polish (60k Diamond): Finished on a 60k diamond charge to achieve sharp facet junctions and a crisp, mirror-like polish across every facet.
Available Now
This rare, oversized Arizona peridot is fully polished, cleaned, and listed in the Shop.
What do you think of how this modified SRB turned out in large-format peridot? Drop your thoughts, questions, or facet preferences in the comments below!
