Curing:
Juniper Ridge Fire Opal lives high in the mountains of southern Oregon. This area typically has significant snowfall, and it remains very wet from the snow melt until June or July. This water seeps into the ground, saturating the opal deposited there. The first order of business every Spring is to pump out our opal-lined swimming hole:
The opal-containing matrix remains damp throughout the season, and the opal you dig will have a high water content. Once removed from the ground, the opal will begin to lose some of that water until it reaches a water content that is stable within its new environment.
As the loss of water takes place, stresses build inside the opal, sometimes resulting in surface crazing or cracks. Because the chemical content, indigenous stresses, and level of water saturation vary from piece to piece, different pieces will craze or crack more than others.
We recommend allowing your opal to “cure” before producing finished works of lapidary art with it. The larger the stone, the more time will be required for it to fully stabilize to the new environment. For smaller pieces we recommend a minimum of several weeks to a few months. For very large pieces, we recommend six months to a year or more.
We presently suggest removing unwanted portions of the opal and paring to rough preforms (slabs, blocks, etc) as soon as possible after digging. We then recommend that the pieces be allowed to stabilize slowly. One strategy is to bury them in a bucket of damp (not wet) sand and then allow the sand to dry out naturally in a sheltered area of moderate temperature.
Regardless of care, some stones will still suffer damage. However, care and patience often pay dividends.
Cutting and Polishing:
Fire Opal is HEAT SENSITIVE, and can break easily if abused by heat during dopping or processing. Whether you are cutting cabochons or faceted stones, we recommend cold-dopping your pieces to avoid breakage.
Fire Opal has no cleavage or crystal structure, so there is no need for special orientation other than for best yield and color.
Juniper Ridge Fire Opal has shown a refractive index of 1.46 in our tests. Our experience indicates a minimum culet angle of 45 degrees is required to prevent “windows” or “fish-eyes” in the finished stones.
Fire Opal is soft and cuts very easily. You can use a coarse lap if you like to remove material quickly. You can cut with a 600 lap and go directly to polish even on fairly large faces. We recommend cerium oxide polish on a Wizard or Plexiglas lap – or Voodoo Magic Polish on a Darkside lap.
Absent those, you can easily make a very good lap from a CD ROM. Use WET-TYPE sandpaper to break the shiny surface on the bottom of the disk. Wash and dry thoroughly and then apply cerium oxide paint or slurry to this surface.
Polishing is best done at very slow speed with very light pressure to prevent scratching.
Patience in curing and care in cutting will yield finished gems of stunning color:
