zircon |
(ZUR - con)
|
BUYER’S OVERVIEW:
Zircon is one of the oldest members of the gem community and is attracting attention due its unique properties. Zircon has outstanding brilliance and very strong dispersion or fire, (the tendency to split white light into spectral colors). High quality stones are limited in nature but gems of good color and size are available.
COLOR:
Zircon comes in a wide range of colors including; blue, yellow, green, brown, orange, red and colorless with red and blue being the most highly prized.
APPEARANCE:
Transparent, Zircon is a Type II gemstone and is usually included. Top gems should be eye-clean with few or no inclusions visible to the unaided eye. Blue and colorless stones tend to be very lightly included with the other colors being somewhat more included.
Phenomena:
Zircon sometimes exhibits the phenomena of Chatoyancy, a striking three dimensional effect typically seen in tiger eye quartz (rare).
SIZE RANGE:
Blue and green – 1 to 9 carats; faceted stones over 100 carats are known
Orange and yellow – 1 to 4 carats; faceted stones over 100 carats are known
Red – under 3 carats; faceted stones over 10 carats are known
POSSIBLE ENHANCEMENTS & TREATMENTS:
Heat treatment is sometimes used to improve the color of red and blue Zircons. Some brown varieties may be heated to produce blue Zircon, yellow Zircon is rarely heated. Zircons that are not enhanced include rose and rose-orange color from Tanzania, and orange to orange-brown from Cambodia. Heat treatment can make the stone brittle with a tendency to wear along facet edges if not treated with care and may not be stable if exposed to prolonged sunlight or UV light. This does not mean the heated gems cannot be enjoyed. They need to be stored in a soft cloth to avoid damage from other jewelry and not left on a window sill.
HARDNESS:
6 to 7½ on the Mohs scale.
BEST USE OF THE GEMSTONE:
Zircon is not a strong gemstone and as such, earrings, pendants, pins, and tie tacks are probably the safest choice for this stone. Rings should be limited to occasional wear and the stones should be set with a protective setting. Heated stones tend to be brittle and will abrade if not treated carefully.
CARE & CLEANING:
It is best to never expose colored gemstones to cleaning solvents or chemicals of any kind.
Common cleaning methods include:
Ultrasonic: never
Steamer: never
Warm soapy water: safe
Reaction to Chemicals: none
Reaction to Heat: heat sensitive, stone will lose or change color.
Stability to Light: some heat treated stones may revert to their original color after prolonged exposure to sunlight or UV light.
INTERESTING FACTS ABOUT THIS GEMSTONE:
Zircon has been valued since the times of antiquity. Some of the historical names are Jacinth and Hyacinth. The name ‘Zircon’ is thought to be derived from the Persian word ”zargum”, which means “gold-colored”. In the Middle Ages Zircon was said to aid sleep, bring prosperity, wisdom and honor to the owner.
Most gemstones were formed in the earth millions of years ago and Zircon is the oldest known mineral on earth. The Earth formed 4.56 billion years ago, the oldest known zircon samples from Western Australia are more than 4.4 billion years old. Zircon was the first crystal to form in the earth’s crust and the oldest samples are even older than the moon (which formed about 4 billion years ago). Scientists have discovered that Zircon contains trace elements of uranium and thorium, elements with known half-lives. Since uranium decays to lead at a known rate, radiometric dating can be used to estimate the age of Zircon. Zircon also has impressive dispersion, the tendency to split white light into the spectral colors. Zircon is (1.810 – 2.024) approaching that of diamond (2.417 – 2.419), which means it is an exceptionally brilliant gem.
Zircon is not to be confused with cubic zirconium, a well known diamond simulant. Cubic zirconium is man made and Zircon is 100% natural.
DESIGNATION:
Birthstone for December
Assigned to the “dwarf” planet Pluto
Zircon is one of the oldest members of the gem community and is attracting attention due its unique properties. Zircon has outstanding brilliance and very strong dispersion or fire, (the tendency to split white light into spectral colors). High quality stones are limited in nature but gems of good color and size are available.
COLOR:
Zircon comes in a wide range of colors including; blue, yellow, green, brown, orange, red and colorless with red and blue being the most highly prized.
APPEARANCE:
Transparent, Zircon is a Type II gemstone and is usually included. Top gems should be eye-clean with few or no inclusions visible to the unaided eye. Blue and colorless stones tend to be very lightly included with the other colors being somewhat more included.
Phenomena:
Zircon sometimes exhibits the phenomena of Chatoyancy, a striking three dimensional effect typically seen in tiger eye quartz (rare).
SIZE RANGE:
Blue and green – 1 to 9 carats; faceted stones over 100 carats are known
Orange and yellow – 1 to 4 carats; faceted stones over 100 carats are known
Red – under 3 carats; faceted stones over 10 carats are known
POSSIBLE ENHANCEMENTS & TREATMENTS:
Heat treatment is sometimes used to improve the color of red and blue Zircons. Some brown varieties may be heated to produce blue Zircon, yellow Zircon is rarely heated. Zircons that are not enhanced include rose and rose-orange color from Tanzania, and orange to orange-brown from Cambodia. Heat treatment can make the stone brittle with a tendency to wear along facet edges if not treated with care and may not be stable if exposed to prolonged sunlight or UV light. This does not mean the heated gems cannot be enjoyed. They need to be stored in a soft cloth to avoid damage from other jewelry and not left on a window sill.
HARDNESS:
6 to 7½ on the Mohs scale.
BEST USE OF THE GEMSTONE:
Zircon is not a strong gemstone and as such, earrings, pendants, pins, and tie tacks are probably the safest choice for this stone. Rings should be limited to occasional wear and the stones should be set with a protective setting. Heated stones tend to be brittle and will abrade if not treated carefully.
CARE & CLEANING:
It is best to never expose colored gemstones to cleaning solvents or chemicals of any kind.
Common cleaning methods include:
Ultrasonic: never
Steamer: never
Warm soapy water: safe
Reaction to Chemicals: none
Reaction to Heat: heat sensitive, stone will lose or change color.
Stability to Light: some heat treated stones may revert to their original color after prolonged exposure to sunlight or UV light.
INTERESTING FACTS ABOUT THIS GEMSTONE:
Zircon has been valued since the times of antiquity. Some of the historical names are Jacinth and Hyacinth. The name ‘Zircon’ is thought to be derived from the Persian word ”zargum”, which means “gold-colored”. In the Middle Ages Zircon was said to aid sleep, bring prosperity, wisdom and honor to the owner.
Most gemstones were formed in the earth millions of years ago and Zircon is the oldest known mineral on earth. The Earth formed 4.56 billion years ago, the oldest known zircon samples from Western Australia are more than 4.4 billion years old. Zircon was the first crystal to form in the earth’s crust and the oldest samples are even older than the moon (which formed about 4 billion years ago). Scientists have discovered that Zircon contains trace elements of uranium and thorium, elements with known half-lives. Since uranium decays to lead at a known rate, radiometric dating can be used to estimate the age of Zircon. Zircon also has impressive dispersion, the tendency to split white light into the spectral colors. Zircon is (1.810 – 2.024) approaching that of diamond (2.417 – 2.419), which means it is an exceptionally brilliant gem.
Zircon is not to be confused with cubic zirconium, a well known diamond simulant. Cubic zirconium is man made and Zircon is 100% natural.
DESIGNATION:
Birthstone for December
Assigned to the “dwarf” planet Pluto