Cutting Mexican Purple Passion Agate

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By Russ Kaniuth

Mexico has long been a source of brilliant colored banded and lace agates, but, for the last couple of years, one agate, in particular, has generated a lot of attention: Purple Passion! This agate has so many beautiful characteristics, with its wide array of colors ranging from soft pink to lavender to deep dark purple and flowering patterns that largely resemble Agua Nueva agate. This agate seems to come in nodules, but actually, its more of a seam agate and usually comes in smaller chunks.

Savvy Selecting

When shopping for Purple Passion, there are a few variances to look for in the rough. Some will include quartz as its matrix, with some fantastic purple agate swirls running through the center. Additionally, other chunks will be encrusted with its host rock and surrounded by the flowering patterns, much like you see in Agua Nueva agate.

Helpful Hint: It’s always best to wet this material to see its colors and whether it will have nice patterns running through it.

Finding Fractures

One thing to look out for when working with Purple Passion is the presence of fractures running through the fortification at the center of each piece. If you buy your material all slabbed up or at least face cut, to begin with, you will see if the center has these fractures. If you come across pieces with fractures, it’s certainly not the end of the world, and can be easily worked around, but it’s nice to find the high-grade pieces that are unblemished.

Other things to watch for are Purple Passion with spots of agate in the host rock. While this does provide a beautiful effect when designing cabs, it will also give you a challenge with varying hardnesses, as the host rock is much softer than the agate and tends to undercut.

When beginning to cut slabs, its best to wet your material, in order to determine which face to start. Since most of this material is smaller in size, I suggest hand cutting on a 10-inch trim saw. Hand-cutting allows you to see if it yields the patterns you are looking for or gives you the ability to easily change directions and cut from other angles without reloading a vice each time. Generally, since this material runs in seams, it’s easy to find a good starting point and continue slabbing in the same direction.

Successful Steps for Cutting Cabs

  1. Once your slabs are cut and prepared to trim out your preforms, bench test your pieces to ensure you don’t run into any hidden fractures that could fall apart in the beginning stages of cabbing.
  2. Lightly tap the slabs on the workbench or a hard surface, and check each piece’s stability. I generally start on the 80 grit wheel to shape and dome each preform.
  3. After you have your preform cab shaped, you can start smoothing it out on a 220 grit steel wheel, or I like to use a 140 grit soft resin wheel on agates instead. (The 140 grit wheel smoothly removes all the deep scratches from the 80 grit and will continue to remove material while smoothing out the dome and edges, leaving very little work for the 280 grit wheel.)
  4. Once you move to the 280, all you have to do is remove any existing scratches. Be sure to have a good light source nearby, so when you occasionally dry off your cab and check for any existing scratches, you will be able to see them in the darker colored areas that usually are hard to see. If you miss them at this stage, they will guarantee to show up once you go further and start polishing.
  5. Once all the scratches are gone from the 280 stage, move to the 600 grit wheel and start polishing. At this point, dry the cab and check once more for scratches, and it should already look as if it’s polished. Keep in mind, if any scratches exist, they will show up at this point; if there are none, you are good to continue to the polishing stages by moving on to the 1200 grit wheel.

Purple Passion is a great agate to work with and doesn’t need any special tricks to bring the polish to a mirror shine, you can finish at 8k grit or 14k grit, and that will give you a beautiful cab.

Polishing Tip: If you desire a more mirror polish, cerium oxide on a leather buff will certainly do the trick but go slow and don’t allow the stone to heat up, because it could very well fracture.