Those born in October enjoy two spectacular birthstones to commemorate their birthdays-opal and tourmaline. Both October birthstones have endless color combinations and beautiful coloring characteristics.
Opal is a birthstone for October, also the gem of the 14th anniversary. Opal is the world's most popular phenomenal gem. Many cultures have credited opal with supernatural origins and powers. Arabic legends say it falls from the heavens in flashes of lightning. The ancient Greeks believed opals gave their owners the gift of prophecy and guarded them against disease. Europeans have long considered the gem a symbol of hope, purity, and truth.
Opal contains up to 20% water trapped in its silica structure. Experts divide opals into many different categories, Four of the main types are:
1) White Opal:- Play of color against a white or light gray body-color
2) Black Opal:- Play of color against a black or other dark bodycolor
3) Fire Opal:- Doesn't show a play of color, yellow, orange, Or red body color, known as Mexican opal, Gold opal, Or Sun opal
4) Boulder Opal:- Play of color against light to a dark background. host rock fragment or metrix are part of the finished gems
Mineral: Hydrated Silica
Color: All colors
Refractive index: 1.37-1.47
Specific gravity: 2.15 ( 0.08, -0.90)
Mohs Hardness: 5 to 6.5 on the Mohs scale
Treatment: Suger & Smoke, Impregnation & Assemble.
Sources / Origin:
Black & White opal: Australia and Ethiopia
white opal: Brazil
Fire opal: Mexico and Brazil
Care and cleaning: Warm soapy water is always safe. Ultrasonic and steam cleaning are not recommended.
TOURMALINE'S FACTS: Tourmaline is a birthstone for October, along with Opal, also the gem of the 8th anniversary.
Tourmaline's name comes from toramalli, which means "Mixed Gems" in Sinhalese (a language of Sri Lanka). Tourmalines are groups of minerals that share the same crystal structure but have slightly different chemical and physical properties. They're all silicates that share the elements aluminum, boron, and fluorine, but contain a complex mixture of other elements like sodium, lithium, calcium, magnesium, manganese, titanium, copper, and iron. So come in a wide variety of exciting colors. In fact, tourmaline has one of the widest color ranges of any gem species.
Gemologists use a tourmaline's properties and chemical composition to define its species. The major tourmaline species are elbaite, liddicoatite, dravite, uvite, and schorl. It occurs in various shades of almost every hue, and there are a number of trade names for its colors varieties;
1) Chrome tourmaline:- A vibrant green tourmaline that's colored by traces of vanadium, chromium, or both.
2) Indicolite:- Dark violetish blue, blue and greenish-blue, colored by iron.
3) Paraiba tourmaline:- Rare, expensive, vibrant greenish blue or intense violet-blue elbaite tourmaline, originally found only in Brazil's Paraiba state in 1989. traces of copper cause the paraiba tourmaline line's extraordinary colors. sources; Brazil, Nigeria, and Mozambique.
4) Rubellite:- Red, Pink to red, purplish red, orangy red, or brownish red, color from manganese. Sources: Brazil, Nigeria, Afghanistan, and Mozambique.
5) Parti-colored / Bi-color Tourmaline:- Tourmaline with more than one color. One of the most common combinations is green and pink. But many others are possible. Gems that show color zoning with two or more colors.
6) Watermelon tourmaline:- Pink in the central zone surrounded by a green overgrowth.
- Elbaite Na(Li1.5,Al1.5)Al6Si6O18(BO3)3(OH)4
- Dravite NaMg3Al6Si6O18(BO3)3(OH)4
- Liddicoatite Ca(Li2Al)Al6Si6O18(BO3)3(OH)3F
- Chromedravite NaMg3Cr6Si6O18(BO3)3(OH)4
- Color: All colors
- Refractive index: 1.624 to 1.644
- Birefringence: 0.018 to 0.040
- Specific gravity: 3.06 ( 0.20, -0.06)
- Mohs Hardness: 7 to 7.5 on the Mohn scale
- Sources/ Origin:- Afghanistan, Brazil, Madagascar, Mozambique, Nigeria, and Namibia.
- Stability: Tourmaline is generally stable to light and isn’t affected by exposure to chemicals, but heat can damage a tourmaline. High heat can alter the color, and sudden temperature changes (thermal shock) can cause fracturing.
- Treatment: Some tourmalines might have been treated to improve their color. The two most important tourmaline treatments are heating and irradiation. Changes resulting from heat treatment are stable and undetectable. Gems with abundant liquid inclusions can’t withstand heat treatment. Color changes due to irradiation can fade with exposure to heat or bright light.
- Cleaning: Warm, soapy water is the best method for cleaning tourmaline. The use of ultrasonic and steam cleaners is not recommended.