NOVEMBER BIRTHSTONES – CITRINE is the transparent, pale yellow to brownish orange variety of quartz. Citrine is rare in nature. In the days before modern gemology, its tawny color caused it to be confused with topaz. Today, its attractive color, plus the durability and affordability it shares with most other quartzes, makes it the top-selling yellow-to-orange gem. In the contemporary market, citrine’s most popular shade is an earthy, deep, brownish or reddish orange.
Mineral: Quartz;
Chemistry: SiO2;
Color: Yellow to orange to orangy red;
Refractive index: 1.544 to 1.553;
Specific gravity: 2.66 (+0.03/-0.02);
Mohs harness: 7;
COLOR: Vivid yellows, reddish oranges, and earth tones are popular with consumers;
CLARITY: Eye-visible inclusions are not common in citrine. If present, they decrease its value;
CUT: Citrine might be carved, custom-cut, or calibrated for jewelry use;
CARAT WEIGHT: Citrine is available in a wide range of sizes for setting into a variety of jewelry styles;
NOVEMBER BIRTHSTONES – TOPAZ Honey yellow. Fiery orange. Cyclamen pink. Icy blue. In warm or cool tones, topaz is a lustrous and brilliant gem. Topaz actually has an exceptionally wide color range that, besides brown, includes various tones and saturations of blue, green, yellow, orange, red, pink, and purple. Colorless topaz is plentiful, and is often treated to give it a blue color. Topaz is also pleochroic, meaning that the gem can show different colors in different crystal directions.
Mineral: Topaz;
Chemistry: Al2(F,OH)2SiO4;
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 harness: 8;
COLOR: The most valued topaz colors are orangy red to red. Blue gems are widely available;
CLARITY: Topaz used in jewelry is typically eye clean with no visible inclusions;
CUT: Topaz crystals are usually columnar, and cut as oval or pear shapes to improve yield;
CARAT WEIGHT: Topaz often forms as large crystals. These can yield sizable cut gems~
30 March 2019
