About Unique Semiprecious Stones: Fake Gemstone Beads

One of the oldest techniques for enhancing or faking stones is dying.  It’s relatively easy with porous stones like howlite which can be dyed to look like turquoise where the pores and spaces between the micro crystals allow dye to penetrate.  However, single crystal gems like aquamarine and quartz are not good candidates because the dye will only penetrate surface fractures.  We want to share our experience identifying fake beads purchased in the heart of aquamarine and tourmaline pegmatite mining country in mineral rich Minas Gerais , Brazil.

Our trip to Brazil was a group tour specifically organized for studying and purchasing gemstones and mineral specimens.  It was sponsored by the Los Angeles Museum of Natural History so we were among several gem experts.  Over a two week period, we visited numerous gemstone mines, dealers, museums, and gem shows.  At every location in every town we were eagerly greeted by 5 to 10 persistent “street dealers” offering cut gemstones, beads, and mineral specimens at ridiculously low prices.  We were fully aware that some offerings were fakes and some were real, but the prices were so low it really didn’t matter much at the time.  Because aquamarine and other beryl gemstones were abundant in the area, one of our purchases from a street dealer was aquamarine, citrine, green tourmaline, and amethyst chip beads. 

 Recently we decided to use these beads to make an attractive necklace.

Necklace Before Tumbling

After finishing necklaces our standard practice is to use a rock tumbler with steel shot to clean and polish the silver.  After the short tumbling process we looked at the necklace and discovered that the beautiful aquamarine and citrine was only clear quartz.

Necklace After Tumbling

This was the bad news. The good news was that we made the discovery and not one of our customers.  Our mistake was to assume that these beads were real instead of checking them out.  In less than 5 minutes we could have identified the fake beads by simply wiping them with a cloth soaked in rubbing alcohol or acetone. When wiped with the cloth the aquamarine turned white and the cloth turned blue.  Both the citrine and aquamarine were fakes, but the tourmaline and the amethyst were real.  One further surprise, we like the necklace better without the dyed beads!

Silver and Stones is always interested in learning more about how to identify fake gemstones.  Can you share a similar experience?

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Jewelry Making Tips: Soldering Dissimilar Metals

All sterling silver oxidizes (tarnishes) over time.  But, if the components of a pendant, for example, are joined with Easy instead of Hard Solder, the soldered area may discolor more rapidly.  Silversmiths have three choices when silver soldering jewelry.

In all three cases the jewelry will look the same initially. The three choices are:

  • Easy Solder which melts at 1325F
  • Medium Solder– 1390F
  • Hard Solder– 1425F

Since sterling silver will melt at 1640F, it’s “easier” to join components without distorting the sterling silver or melting other soldered joints with Easy Solder because it melts 315 degrees below the sterling silver. The margin of error with Hard Solder is only 215 degrees. The problem is that Easy and Medium Solder contain more copper and zinc but less silver than Hard Solder. Consequently, softer solders:

  • have less strength
  • discolors more rapidly due to dissimilar metal corrosion
  • makes jewelry almost impossible to repair if needed

The bottom line is that it’s higher quality jewelry if the silversmith uses Hard Solder.  Before you buy sterling jewelry or commission a custom piece, ask your jeweler or silversmith if their sterling silver jewelry is made using hard solder.

This may explain why your jewelry discolors in the soldered areas and maybe it will help you avoid the problem in the future.   More jewelry making tips are coming!

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Hot Rockhounding Spots: Bouquet Agates

Bouquet Agate

Bouquet agates are agates embedded with tiny colorful flower “bouquets” rather than the more common banded agate like those in the header photo above. Where are these most lovely and rare agates found? Bouquet agates are found in the Trans Pecos region which extends from the Chihuahua desert in northern Mexico through the scenic, arid mountains of Big Bend National Park and Gaudalupe  National Park in west Texas. Our rock hunting adventure began in the U.S. border town of Presidio, Texas and took us to the football field sized agate bed of  Manual Benavides which is 12 miles south of Lajitas, Texas.  This agate bed is so remote we wondered how it was ever discovered! Yet getting there (with a guide) is only the start.  Now the hard work really begins; the agates are typically buried 6-12 inches underground just above a layer of green volcanic basalt. Uncut agates usually range in size from 1-5 inches in diameter, are egg shaped and absolutely ugly! 

Bouquet Agate Rough

 Only when hand cut by a diamond saw are the delicate, colorful bouquets revealed.  However, about 9 in 10 are disappointments with only clear chalcedony centers, so we gather as many as possible in the dry Mexico sun hoping for a few of the spectacular bouquets!   To see many more photographs of these incredible stones go to Matt Dillon’s FlickR site: http://www.flickr.com/search/?q=bouquet&w=97769244%40N00  

Check back soon for more of our rock hounding adventures in Mexico, the American Southwest, Brazil, and Namibia and beyond!  Silver and Stones is always interested in learning about interesting rock hounding adventures.  Can you share your experiences with remote rock hounding sites?

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About Unique Semiprecious Stones: Turquoise Tidbits

Why is turquoise one of the most popular and valuable semiprecious stones in today’s jewelry market?  One reason is its color which varies from almost white to intense green to greenish blue to sky blue.

Turquoise Cabochons

Another reason is that it looks great in multiple settings from casual to elegant.  Almost all deposits of turquoise in the United States are found in volcanic hydrothermal desert regions like Arizona and Nevada within 180 feet of the surface.  

Morenci Turquoise Pendant

High quality untreated turquoise is rare.  Most turquoise bought today will be treated with a generally accepted process called turquoise stabilization.   In the stabilization process, nuggets are dried and then an epoxy is forced into the stone under intense pressure.  The treated turquoise is sealed and allowed to dry slowly.  The epoxy heightens color and makes the stone harder.  Stabilized turquoise can be cut and polished as well or better than natural turquoise.  

Be cautious because turquoise has been faked for centuries.  Blue resin can be made to look like turquoise but you can tell if it’s fake by touching it with a hot needle.  It will burn and give off a plastic odor.  Also, it’s much lighter in weight.  There are other minerals that can be made to look like turquoise.  The best example is howlite stone with spider web veins like the one in the photo.     

Polished Howlite Stone

It’s softer, lighter, cheaper, more common and can be dyed to look exactly like turquoise.  If you can see white inside of a bead’s hole, it’s most likely howlite. 

Dyed Howlite

Take care of your beautiful turquoise by cleaning it occasionally with mild soap and warm water.  Inks, cloth dyes, fruits, and oily skin can stain your turquoise. Extended exposure in strong sunshine may cause cracks and color fading.  Never store your turquoise in an airtight package because it can loose its luster.     

 Now for the hard question.  How do you keep the fabulous sterling setting highly polished while allowing air to the turquoise?  Any ideas?  My silver always seems to need polishing. 

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Lapidary Tips: Fast Inexpensive Lapidary Slab Saw

Lortone 14 Inch Oil Cooled Slab Saw

 After finding or acquiring lapidary rough the work has just started in terms of cutting high quality slabs for cabbing.  Cutting rough into slabs can be time consuming especially using expensive slow cutting self feed diamond saws with oil lubricant like the one shown here.  Investment for diamond saws like these exceeds $1500. Using oil lubricated diamond saws may be necessary for cutting specimens, display slabs, or large rough because the slab surface is smoother for polishing. But for cabbing slabs, it’s simply too expensive and time consuming because of slow cutting speed and surface oil removal from the slabs before cabbing.   

If you want to reduce cost and improve productivity, start hand cutting rough using a water cooled tile saw.  It’s at least 10 times faster because cutting speed is much faster and it eliminates all of the steps for cleaning oil from slabs.  Also, hand cutting allows you to see the rocks cut surface immediately so that you can flip it around if the pattern is not what you want. It’s possible to cut a 5 inch diameter piece of rough into 5 slabs in less than 15 minutes.  Finally, with water you are not breathing and handling oil so it’s environmentally better.     

Modified Lapidary Tile Saw

Hand cut  slabs may not be perfect dimensionally but they will be good enough for cabs. One downside is that saw blade wear is faster but the upside is that the investment required for a tile saw is significantly less. Harbor Freight sells a 10 inch 2.5 horsepower tile saw for about $250.  

 
 
 
 
To make the saw usable indoors you can:
  •  mount a removable modifed plastic storage box over the frame to contain water mist
  • mount a splash shield and light at the end
  • hook up a water feed tube and drain
  • start fast low cost slab cutting
This may appear dangerous but I have cut thousands of slabs with no problems. You can cut hundreds of slabs using a $40 ten inch Ridgid diamond saw blade from Home Depot.  Always wear a face mask to avoid breathing silica carried by the cooling water mist.  
Here’s a summary of the advantages of hand cut water cooled tile saws versus automatic feed oil cooled lapidary saws:
 
  • 5x lower diamond saw investment
  • 10x faster slab cutting
  • No messy oil to remove from slabs
  • Quickly flip rough around to cut the best pattern
  • Environmentally safer water versus oil  

Silver and Stones is always looking for ways to improve safety and be more efficient.  Could you share your tips on increasing productivity, lowering cost, and making it environmentally safer for cutting lapidary slabs?

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