November birthdays have two beautiful birthstones to choose from topaz and citrine. Topaz comes in a rainbow of colors; citrine is prized for its charming yellow and orange hues. Both November birthstones are known to have calming energies while bringing fortune and warmth to the wearer. TOPAZ:- Imperial(Precious) topaz is a birthstone for November and blue topaz is a birthstone for December. Blue topaz is the gem of the 4th anniversary and imperial topaz is the gem of the 23rd anniversary. For centuries, topaz was associated with the color yellow. People assumed that all yellow gemstones were topaz and that all topaz was yellow. Today, we know that topaz occurs in a broad color range that includes various tones and saturations of red, pink, purple, yellow, orange, and brown, as well as blue and green. Topaz can also be colorless. One of the most valuable of these is known as Imperial topaz, which most in the trade consider a medium reddish-orange to orange-red color. There are a couple of special trade names.
1) Imperial Topaz: A widely used trade term for gem-quality topaz of medium reddish-orange to orange-red color.
2) Precious( Sherry)Topaz: A trade term for orange to yellow and brown topaz.
3) Blue Topaz: Naturally colored strong blue gems are extremely rare. Blue topaz treatments produce vibrant blue shades that are uniform and repeatable. Treaters use a combination of radiation and heat to produce blue hues in topaz. Since the 1970s, treatments have brought blue topaz to a broad market. The treatment produces many shades of blue in topaz. Dealers use terms like "London blue" (darker blue), "Swissblue"( lighter blue), and " sky blue"(paler blue).
4) Mystic Topaz: White topaz is coated with a thin layer of titanium on the pavilion, creating a multi-colored iridescent effect.
5) White Topaz: Topaz is commonly colorless, but treatment can produce blue, mystic, and pink.
Color: Yellow, orange, brown, pink to red to purple red, blue, light green, and colorless
Refractive index: 1.619 to 1.627
Birefringence: 0.008 to 0.010
Specific gravity: 3.53
Mohs Hardness: 8 on the Mohs scale
Sources/Origin: Brazil, Madagascar, Myanmar(Burma), Nigeria, and Sri Lanka.
Stability: High heat or sudden temperature changes can cause breaks in topaz. The gem’s color is generally stable to light, but prolonged exposure to heat or sunlight might cause fading in yellow-to-brown, reddish-brown, or dark-brown topaz. Topaz is affected only very slightly by chemicals. Cleaning: It’s important to avoid steam or ultrasound for cleaning topaz: Warm, soapy water works best. Treatment and durability considerations: Besides irradiation and heat treatment, there is another treatment that involves coating colorless topaz with a microscopic layer of metallic oxide compound. The coating is not very durable. It can resist daily wear and tear, but abrasive cleaners or buffing wheels would remove it. It’s safe to use a mild soap solution.
CITRINE: Along with topaz, citrine is a birthstone for November. It's also recognized as the gem that commemorates the 13th wedding anniversary. It's a quartz variety, and a top-selling transparent gem in the yellow to the orange color range. Its name was derived from the Latin word citrus, meaning "citron" ( a fruit closely related to the lemon). This gem combines a warm, attractive color with good wearability and a moderate price an unbeatable combination for many customers. The color comes from a trace of iron. Dealers look for citrines without color zoning or visible inclusions.
Chemical composition: SiO2
Color: Yellow to orange to orangy red
Refractive index: 1.544 to 1.553
Specific gravity: 2.66 ( 0.03/-0.02)
Mohs hardness: 7 on the Mohs scale
Sources/ Origin: Bolivia, Brazil, Madagascar, Mexico, Namibia, Uruguay, and Zambia.
Treatment: Natural citrine is rare. Most citrine on the market is the result of heat treatment of amethyst.
Stability: Abrupt temperature changes can cause citrine to fracture. Some citrine colors can fade with prolonged exposure to intense light. Citrine can also be damaged by hydrofluoric acid, ammonium fluoride, and alkaline solutions.
Cleaning: Citrine can be safely cleaned with warm, soapy water. Ultrasonic cleaners are usually safe except in the rare instances where a stone is dyed or treated by fracture filling. Steam cleaning is not recommended, as citrine should not be subjected to heat.