Pricing Information For Star Opals From Spencer, Idaho


Spencer, Idaho, is the source of very rare and beautiful star opals. “05212008333,” Spencer, Idaho, by andresmh is licensed under CC By-SA 2.0
Spencer, Idaho is the source of very rare and beautiful star opals. “05212008333,” Spencer, Idaho, by andresmh is licensed under CC By-SA 2.0

Question

I love working with opal from Spencer, Idaho. On rare occasions, I turn up a star stone. I know star opals are very rare. So as you can imagine, I’m having a heck of a time trying to put a realistic value on what I cut. Does anyone have any pricing information or guidelines for star opals?

Star Opals, Circa Mid-1970s

I’ve cut both star opals and cat’s eye triplets from Spencer material. They are indeed rare and very beautiful. I would suggest contacting gem shops from the area. They might be able to give you the information you need or put you in touch with local cutters who know the market.

This reference may be old but it might help. Back in the mid-1970s, Lapidary Journal (now Lapidary Journal Jewelry Artist) did a cover story on star opals from Spencer. Check their index or try to find a copy online or at a library. The story and photos may give you a better idea of what to take into consideration when judging quality. The article also explains the cause of this rare phenomenon.

Rick Martin, Martin Designs

While asterism in other gemstones, like this sapphire, is caused by inclusions, the star effect in opals is caused by the diffraction of light from imperfections in the arrangement of silica (SiO2) in the stones. “Star of India,” sapphire, by Katie Munoz is licensed under CC By-SA 2.0
While asterism in other gemstones, like this sapphire, is caused by inclusions, the star effect in opals is caused by the diffraction of light from imperfections in the arrangement of silica (SiO2) in the stones. “Star of India,” sapphire, by Katie Munoz is licensed under CC By-SA 2.0

Suggestions For Pricing Star Opals

Pricing and appraising opals is already a complex art. Pricing star opals is more difficult than you might think. This stone is so rare few people sell it.

Here are some suggestions:

  • Judge the stone’s clarity compared to similar stones on the market, much like you would a blue star sapphire.
  • Consider the stone’s size and its wearability. Usually, the larger the stone the higher the price you can ask, as long as it’s in the “wearable range,” 20 carats or smaller. Over that range, the price per carat drops.
  • Evaluate how complete the star is on your opal. If star opals typically have clear and straight lines, then a stone with a clear, sharp star is not a rarity. However, if the stars are typically not clear or sharp, a stone with a clear, sharp star may command a value 2 to 3 times higher than typical.

This is what gemologists do when they grade a rare stone. However, the price is ultimately dictated by what you want for it and what the buyer is willing to pay.

Douglas LeGrand, GG

Editor’s Note: Check out these pics of star opals. For a look at a doublet made from a star opal from Spencer, Idaho, click here.

Opals are renowned for their play of color and light. “Opal” by Yagan Kiely is licensed under CC By-SA 2.0
Opals are renowned for their play of color and light. “Opal” by Yagan Kiely is licensed under CC By-SA 2.0