How Much is my Jewelry Worth?

How much is my jewelry worth?  I’m asked this at every show.  As a gemologist I can identify the gemstones in your jewelry, but to answer the question of value, the right person to ask is an appraiser.  I’ve asked my colleague, Jeanne Hawk, a GIA Graduate Gemologist, Registered MasterValuer and Certified Insurance Appraiser, to be a guest blogger this month:

Establishing and substantiating the value of an item are what appraising is all about. An appraisal is an opinion of value, a well-researched conclusion that is supported by facts which are interpreted from the marketplace. Most jewelry appraisals are done for obtaining insurance coverage. An insurance appraisal is used to determine the retail replacement value of a jewelry item. Other appraisal types include those done to determine fair market value for estate items and items sold for scrap value.

Many of my clients have jewelry of unknown identification or value. I do consultations to identify the gemstones and/or diamonds and metal karatage to determine what you have and whether you should keep it, insure, or scrap it, as is often the case with outdated gold chains. I’ll let you know the market value if you plan to sell it. And if it’s something you want to insure, I can prepare an appraisal for you.

There are six steps involved in the appraisal process as follows: 1) establish the scope of the appraisal, 2) plan the appraisal, 3) collect and analyze the data, 4) apply a valuation approach, 5) set limitations and contingency conditions, and 6) supply the final estimate of value.

At the present time anyone can call oneself a professional jewelry appraiser. However, self-anointing does not confer expertise. The key is education. A gemologist who has undergone formal gemological training, holds a degree or special education in valuation science, and has buying and selling experience either on a wholesale or retail level has the basic prerequisites of an appraiser. The valuation must be done by an individual with suitable qualifications who has no interest (no bias) in the item. Participation in professional appraising organizations is important, as well. It is critical that any jewelry appraisal be developed and written in accordance with the Uniform Standards of Professional Appraisal Practice (USPAP), authorized by Congress as the source of appraisal standards and appraiser qualifications.

I am a certified Gemoljeanne_cropogical Institute of America (GIA) Graduate Gemologist (GG), qualified to accurately identify and grade the gemstones in your jewelry. As a Registered Master Valuer™ and Certified Insurance Appraiser™, I am trained in appraisal valuation techniques and can appropriately value and appraise your jewelry. All appraisal reports are prepared in accordance with USPAP.

At your appraisal appointment, I will clean, identify, measure, weigh, grade, and photograph your jewelry. Most appointments take 30 minutes; longer appointments may be needed for multiple items. You will leave with your jewelry. In 7-10 business days, once I have completed the valuation part of the appraisal, you will receive your appraisal via email. Payment for the appraisal, and any hard copies requested, is due at the time of your appointment. Would you like to learn more about how the value of jewelry is determined? Find out in my FREE report! Call this 24 hour toll free recorded message to request your report. 1-800-579-3932.

Jeanne Hawk Fine Jewelry Appraisals specializes in gem identification, diamond grading, jewelry appraisals, market value estimations, general consultation, and quality assessments. To best meet my clients’ needs, services are provided by appointment only. I can be reached at 831-359-3449 or via email at info@hawkjewelryappraisals.com to schedule an appointment. The office is located at 5521 Scotts Valley Drive, Suite 235, Scotts Valley, CA 95066. The company website is http://www.hawkjewelryappraisals.com. Give me a call or visit my website today!

 

Turritella Agate – A Snail By Any Other Name …

FTGFN105_a

Fossil turritella agate & garnet necklace (Item FTGFN105)

In last month’s blog I explained that for many gemstone beads, the country of origin may be difficult to determine.  Fossil turritella agate is an exception because it comes exclusively from the Green River Formation in Wyoming, USA.

Turritellas are marine snails (gastropods) with spiral shells.  When fossil snails were found in the Green River Formation, they looked like turritellas and were given that name.  However, it turned out that the snails were in fact an extinct freshwater variety and were renamed Elimia tenera.  By that time, the incorrect name had already become commonly used and the name elimia tenera has never managed to replace the incorrect turritella name.

Turritella fossils are among my favorite fossils to incorporate into my jewelry designs; the fossil snails are creamy to white spirals in a rich brown to almost black matrix.  The polish can be uneven on these stones due to the natural variation in the fossils, but that’s part of what makes each one unique.

The following is directly from http://geology.com/gemstones/turritella/:

“How did Turritella Agate Form?

About 50 million years ago, during the Eocene epoch, the young Rocky Mountains were almost finished growing, and the landscape of what is now parts of Colorado, Utah, and Wyoming consisted of rugged mountains separated by broad intermountain basins. Rains falling on the slopes of these mountains ran off of the land and collected into streams that carried sand, silt, mud, and dissolved materials down into the lakes that occupied the intermountain basins. Over time, these sediments began filling the lakes, and many types of fossils were preserved within them.

Abundant plants and algae grew on the margins of these lakes, providing a perfect habitat and food source for Elimia tenera, the freshwater snail. When the snails died, their shells sank to the bottom of the lake. The snails were so prolific that entire lenses of sediment were composed almost entirely of their shells.

After these layers were buried, groundwater moved through the sediments. Small amounts of microcrystalline silica that were dissolved in the groundwater began to precipitate, possibly in the form of a gel, within the cavities of the snail shells and the empty spaces between them. Over time, the entire mass of fossils was silicified, forming the brown fossiliferous agate (also known as chalcedony) that we know today as Turritella agate.”

References:

FTGVE102_Nov15_a

Fossil turritella agate & garnet earrings (Item FTG2)

http://geology.com/gemstones/turritella/
https://en.wikipedia.org/wiki/Elimia_tenera

Natural or Treated? Common Gemstone Treatments

Did you know that many gemstones are routinely treated (also called enhanced)?
These treatments are generally used to change or improve the color, clarity, or durability of a gem. Some gemstones are significantly more valuable if they are not treated, but treatments allow many more beautiful stones to be made available to consumers. It is important to understand treatments are not inherently “bad” but that legally,  they must be disclosed to the customer if they are not permanent, require special care, or if they affect the value of the stone.

Here are some of the most common gemstone treatments, why they are used, and a few examples of the gems that may be treated in this way.  Sometimes more than one treatment is used to achieve a desired result.

Process: Bleach
Why: Improve color
Examples: Pearls and jadeite jade are commonly bleached to remove undesirable coloring.

PEGFN102_V2a

PEGFN103_a Pearls are commonly bleached (top) and are often dyed or irradiated (bottom)

Process: Dye
Why: Change or improve color
Examples: Stones such as lapis lazuli may be dyed darker blue to improve their color. White stones such as howlite or pearls may be dyed to resemble other stones such as turquoise or just to provide fun options for jewelry design.

Process: Fracture filling with dyes, glass, oils, polymers or resins
Why: Improve clarity and/or color
Examples: Emeralds are commonly fracture-filled to improve their clarity.

Process: Heat
Why: Change or improve color
Examples: Sapphires and amber are commonly heated to improve clarity. Tanzanite changes from brown to blue when heated and amethyst can be turned yellow and is sometimes then sold as citrine.

Process: ––Irradiation
Why: Change or improve color
Examples: Some gray pearls have been irradiated.  Colorless topaz is both heated and irradiated to create blue gems.

–Process: Stabilization/Impregnation with plastic, polymers or wax
Why: Improve durability and appearance
Examples: Soft stones such as turquoise, lapis lazuli and rhodochrosite are commonly stabilized.

Other treatments not covered here include high pressure high temperature (hpht), surface coating and lattice diffusion. You can learn more about these as well as the treatments above by clicking the GIA link below.

Sources:
Code of Federal Regulations Part 23 – Guides for the Jewelry, Precious Metals, and Pewter Industries
Gemological Institute of America (GIA) – Gem Treatments

Quartz – so many gems, so much confusion!

Quartz, chalcedony, agate, jasper … What’s the difference?

The quartz and chalcedony gems provide a wide range of beautiful colors and patterns with very good durability. Although they all have the same basic chemical formula, SiO2, different impurities and/or conditions when the minerals form create different end results.

First we’ll define two major groups based on crystal size: quartz and chalcedony (pronounced kal-sed-n-ee).

Quartz varieties have crystals that can be seen with an optical microscope (and sometimes with the naked eye).

AMSSN102_a

Amethyst (item AMSSN102)

Some quartz varieties commonly used in jewelry include:
Amethyst – purple
Ametrine – purple and yellow in the same stone
Citrine – yellow
Rock crystal – colorless
Rose quartz – pink
Smokey quartz – brown

Chalcedony varieties are cryptocrystalline which means that individual crystals cannot be seen, even with the use of an optical microscope.  Chalcedony gems are subdivided into two groups: agate and jasper.

Agate has angular or curved banding. 

Blue lace agate  (item BASSN101)

Blue lace agate
(item BASSN101)

Some agates used in jewelry include :
Blue Lace Agatelight blue bands in a lacy or wavy pattern
Botswana Agate banded with fine parallel lines of white, purple, or peach
Crazy Lace Agatetwisting and turning bands of various colors
Eye Agatebanded, concentric rings that are perfectly rounded
Fire Agate  –  Form of Agate or Chalcedony that is iridescent

Jasper is a “general variety term for opaque chalcedony of any color or combination of colors except solid black or specially named material” (GIA).

Mixed jasper necklace (Item JSGFN101) displayed on ocean jasper slab

Mixed jasper necklace (Item JSGFN101) displayed on ocean jasper slab

Examples of “specially named” varieties include:
Bloodstone – dark green with red spots
Carnelian – orange
Chrysoprase – apple green
Onyx – banded, black and white
Sardonyx – banded, brown/red and white

To add to the confusion, a number of gems don’t follow the naming conventions:
Moss agate – green inclusions, not banded
Onyx- banded, should be agate
Sardonyx – banded, should be agate

There are also many quartz minerals that are not beautiful or rare enough to be considered gems, such as chert and milky quartz.

With all these beautiful colors and patterns to choose from, there’s a quartz or chalcedony gemstone for everyone! Which is your favorite?

Information sources:
Gem Identification Lab Manual, Gemological Institute of America, 5/2012
http://www.minerals.net
http://www.wikipedia.org

Jade – Confused? Here’s Why:

I’m often asked if I make jade jewelry. The answer is yes… and no. That’s because there are two different gemstones that can correctly be called jade. They are similar in hardness and can sometimes be difficult to tell apart visually, but they are very different chemically. Both have been used for thousands of years for tools, decorative carvings and jewelry.

Things that ARE jade:

Nephrite Jade: chemical formula Ca2(Mg,Fe)5(OH)2. Nephrite is found in many countries including along the west coast of North America (sometimes called Canadian or B.C. jade) and also in Australia and New Zealand where it is often used for carved pendants. I’ve most commonly seen it in bright medium and dark greens to almost black but it can also be grayish or brown as well. Nephrite is generally more affordable than jadeite. Here’s an example of one of my recent pieces incorporating nephrite:

FOSSN104_a

Fossil orthoceras with nephrite jade (item FOSSN104)

Jadeite Jade:  chemical formula NaAlSi2O6. Jadeite is also found in the US and Canada, parts of Europe, and Myanmar. This is the jade that comes in colors including apple-green, white, and pale purple. It often has a mottled appearance. It is available as beads but tends to be very expensive.

Jadeite is commonly treated and has been categorized into 3 types based on this:
Type A – Natural, untreated, may have a surface coating of wax; “true” color.
Type B – Chemically bleached to remove impurities then impregnated with wax or polymers.
Type C – Dyed to enhance color; often chemically bleached and/or impregnated with wax or polymers.

PEGFN102_a

Aventurine and cultured pearl necklace (item PEGFN102)

Gems that can be confused with jade:
Aventurine: A quartz that gets its green color from inclusions of green chlorite mica. Aventurine is harder and significantly less expensive than either type of jade and has beautiful color. I often use it in my jewelry.

Unfortunately, some gemstones are given  trade names that are descriptive rather than accurate. Some trade names are intended to make a stone sound more expensive or desirable. Here are a few examples with their actual identity:
African Jade: grossular garnet
Australian Jade: chrysoprase
Malaysia Jade: dyed translucent quartz
Mountain Jade: dyed high-grade dolomite marble
New Jade: serpentine
Olive Jade: serpentine

Buyer beware – don’t pay jadeite prices for nephrite, aventurine, or any of the other stones I’ve listed above. Proper gemological testing can easily identify these gemstones.

For more information:
http://www.gia.edu/jade

Nephrite:
http://www.mindat.org/min-2881.html
http://www.gemdat.org/gem-2881.html

Jadeite:
http://www.gemdat.org/gem-2062.html
http://www.mindat.org/min-2062.html

Amethyst: Power to the Purple!

amethyst

Amethyst crystals, cut gem, and beads

February’s birthstone is amethyst, the purple variety of quartz.

Last month I told you about the many different colors of garnets, which are caused by differences in chemical formula. Pure quartz (chemical formula SiO2) is colorless (and is called “rock crystal” in the jewelry industry). The different colors of quartz* are caused by defects in the crystal structure rather than by a consistent change in the  chemical formula. This often causes different amounts of color within even a single crystal (“color zoning”). For amethyst, iron, and possibly aluminum, impurities are believed to cause the purple color.

Amethyst deposits are found all over the world; many of the large mineral specimens come from Brazil and Uruguay, but other sources for the gem include Russia, Czechoslovakia, Zambia, and the United States. It is not uncommon to find relatively large crystals which makes this a very affordable gem, even in large sizes.

Other facts – Amethyst:

  • is the gemstone for those celebrating their 6th or 17th wedding anniversary
  • was believed to prevent intoxication—amethystos means “not drunk” in ancient Greek
  • is sometimes found in combination with citrine and is then known as “ametrine”
  • when heated can change color to become a golden citrine
  • has a hardness of 7 on the Moh’s scale

*Other quartz gemstones include citrine (yellow), aventurine (green), rose quartz (pink), tigers eye (brown), smokey quartz (brown or gray) and chalcedony (which includes jaspers and agates).

Sources:

  • Gemological Institute of America, Gem Encyclopedia page on amethyst: click here.
  • Manual of Mineralogy, 20th Edition, Cornelis Klein and Cornelius S. Hurlbut, Jr., 1977.
  • GemSelect

Garnets are Red … Sometimes

January’s birthstone, garnet, is generally associated with the color red. But did you know garnets also come in orange, green, brown, and other colors?

Garnets are actually a group of gems with similar, but slightly differing chemical formulas.  The generic formula is A2B3(SiO4) where A is calcium, magnesium, iron or manganese (Ca, Mg, Fe, Mn) and B is aluminum, iron or chromium (Al, Fe,Cr). The different combinations of elements create the different species of garnet (listed below with their common colors). Color can be a very helpful diagnostic feature when identifying some (but not all) gems.  For instance, spessartine garnet must always have an orange color component.

min_garnet

Almandine garnet collected at Gore Mountain in New York (left), spessartine garnet crystal (locality unknown, right)

  • Pyrope: medium to dark reddish orange, red through slightly purplish red to pale pink, colorless
  • Almandine: brownish orange to brownish red to purplish red
  • Spessartine: orange, brownish orange, yellowish orange, reddish orange, and red-orange
  • Grossular: medium to dark orange, medium to dark green to yellowish green, colorless
  • Andradite: yellow to slightly greenish yellow or brown, green through yellow-green
  • Uvarovite: light to dark green through yellow-green to brownish green
  • Hydrogrossular: pink, green, brownish pink, white, gray

Because of the range of chemical formulas possible, garnets may also be mixes of more than one species.  In addition, some species have subspecies (called varieties).  Some examples are Demantoid (a variety of Andradite) and Hessonite (a variety of Grossular)

Some garnets also display “phenomena” such as stars, cat’s eye, and color-change due to features of that stone that affect how light is reflected and/or transmitted.

Other facts – Garnet: 

  • is the gemstone for those celebrating their 2nd wedding anniversary
  • is used as an abrasive
  • has been used in jewelry since ancient times
  • can be found in all three major rock types: igneous, sedimentary and metamorphic
  • has a hardness of 6.5-7.5 on the Moh’s scale

and comes in colors to please almost everyone!

GASSN102_a

Sources:

  • Gemological Institute of America, Gem Encyclopedia page on garnets: click here.
  • Gemological Institute of America, Gem Identification Lab Manual, 5/2012
  • Manual of Mineralogy, 20th Edition, Cornelis Klein and Cornelius S. Hurlbut, Jr., 1977.

Gift Giving: Gems with Significance

Most people are aware of birthstones, the gems associated with the month a person was born in, but did you know that specific gemstones are also associated with anniversaries, zodiac signs, historic customs, religions, and metaphysical healing?  Here’s a partial guide to help you with some classic or perhaps some unusual options to give a jewelry gift with extra meaning.

TUSSN101

Turquoise

Birthstones (traditional and modern):
January: garnet
February: amethyst
March: aquamarine or bloodstone
April: diamond or rock crystal (quartz)
May: emerald or chrysoprase
June: alexandrite, moonstone or pearl
July: ruby or carnelian
August: peridot or sardonyx
September: sapphire or lapis lazuli
October: opal or tourmaline
November: topaz or citrine
December turquoise, zircon or tanzanite

Anniversary Gemstones: (it’s a long list so here’s a link)                                         http://gemologyonline.com/anniversary.html

Chakra Gems: Different sources tend to provide slight variations on gems for metaphysical purposes.  Here’s are some links (this is not an area in which I have expertise so you may find better options):

http://healing.about.com/od/astrology/a/zodiacstones.htm                                                               http://gemologyonline.com/chakra.html                           http://balance.chakrahealingsounds.com/chakra-colors-stones/

 

Hematite, Imitation Hematite and Disclosure

Hematite

Hematite is a naturally occurring mineral with the chemical formula Fe2O3. It is mined as an ore of iron and you’ll notice it’s quite heavy because of that iron content. It is commonly metallic steel gray to reddish brown.

HESSN101_a

Imitation hematite necklace on natural hematite specimen

Imitation Hematite

You may notice that hematite jewelry is relatively inexpensive compared to other gemstone jewelry. There’s a very good reason for that – almost all hematite beads are imitation. This means that they look like the natural mineral, but they are man-made.  This is also why you’ll see imitation hematite in so many more shapes than natural gemstones (including the rings in the necklace shown above). The larger bead companies that sell on-line are generally very good about providing information on synthetics, imitations and treatments and may use names like “hematine” and “hemalyke” to denote imitation hematite. Magnetic hematite is also an imitation gem. Imitation gemstones are not “bad” – they have a place in the gem world in providing beautiful and generally more affordable versions of rare gemstones. I love the look of hematite and often create and wear imitation hematite jewelry.

Disclosure

In the jewelry industry, ethical dealers tell customers when a gem is imitation, synthetic or has been treated in some way.  This is called disclosure. However, when at bead shows, I’ve learned that some sellers are not as knowledgeable about their products as they should be and do not provide this information.  So, when I buy beads, I ask lots of questions and consider the items carefully before purchasing.  This does not mean that I have not been fooled!  When buying at gem shows, it’s just not possible to have all the necessary equipment to do testing. I generally assume that any “hematite” beads that I buy are imitation and you probably should too!

Thanks for reading!

Gem vs. Mineral

What’s the difference between a gem and a mineral?

Some, but not all, minerals are gems, and some, but not all, gems are minerals.  Confused?  Good, then we’re ready to start.

amethyst

Amethyst is both a mineral and a gem

A GEM has the following properties:

  • Rarity
  • Beauty
  • Durability

A MINERAL has these properties:

  • Inorganic
  • Naturally occurring
  • Set chemical formula or range of formula
  • Solid with unique crystalline atomic structure

(A rock is composed of more than one mineral although a large mass of a single mineral can also be called a rock.)

In general, the properties for gems are much more loosely defined than those for minerals.  Let’s look at some of these properties.

Rarity: Rarity describes how common a gem is and can change as gem deposits are mined out or new sources found. Rarity is also relative to each individual gem; for instance, large inclusion-free amethysts are common, but large inclusion-free emeralds are extremely rare. Generally, the “cleaner” and larger the gem, the rarer and therefore more expensive it will be.

Beauty: Not everyone agrees on what is beautiful, but there are gems for just about everyone’s taste.

Durability: Durability is a gemstone’s ability to withstand wear, heat, and chemicals. Durability consists of three properties: hardness, toughness, and stability. Hardness means how well a gemstone resists scratches and abrasion. Toughness describes how well a gemstone resists breaking and chipping. Stability means how well a gem resists chemicals and temperature changes. (http://www.gia.edu/diamond-care-cleaning)

Inorganic: Not a previously living plant or animal.

Naturally occurring: Not made by humans.

Set chemical formula or range of formula and unique crystalline atomic structure: This is what creates specific crystal shapes and consistent properties for a given mineral.

Examples of gems that are not minerals:

  • Pearls, fossils and amber (“organic” gems)
  • Any synthetic gem (not naturally occurring)

Examples of minerals that are not gems:

  • Gypsum, mica (not durable)
  • Milky quartz (not rare)
  • Hornblende (not beautiful as a gem)

When you look at a piece of gem jewelry, consider how these factors came together when you admire its beauty!