Tourmaline is a craft name for tourmaline, which is a type of tourmaline that has reached the level of jewelry in the tourmaline family. It is a borosilicate crystal containing chemical elements such as aluminum, iron, magnesium, sodium, lithium, and potassium, presenting various colors.
The English name Tourmaline is derived from the ancient Sinhalese word Turmali, meaning “mixed gemstone”. The composition of tourmaline is complex, and its color is also diverse and varied. The international jewelry industry generally divides tourmaline into commercial varieties based on color, with darker and more vibrant colors having higher value. When making a purchase, attention should be paid to color, transparency, and purity.
origin
In 1500, a Portuguese exploration team discovered a gemstone in Brazil that shone with rainbow lights. Like a rainbow shooting from the sky towards the center of the earth, ordinary stones bathed in the rainbow acquire various colors that the world encompasses along the way, being refined and crystal clear. This gemstone hidden at the foot of the rainbow is called tourmaline by later generations and is also known as the “rainbow that fell into the human world”. At present, tourmaline, ruby, sapphire, aquamarine, tanzanite, emerald and other gemstones with natural colors are classified as colored gemstones, which are deeply loved by the public and have huge market value potential.
colour
The color of tourmaline is the most abundant among all kinds of gemstones. Due to the fact that tourmaline belongs to a complex borosilicate mineral with a chemical molecular formula of Na (Mg, Fe, Mn, Li, Al) 3Al6 [Si6O18] [BO3] 3 (OH, F) 4, metal ions such as iron, magnesium, lithium, manganese, and aluminum can replace each other, and the different contents of each ion directly affect the color and type of tourmaline. Rich iron tourmaline is black and green in color; Rich magnesium tourmaline displays yellow or brown; Rich in lithium, manganese, and cesium, tourmaline displays rose red, pink, red, or blue colors; Rich chromium tourmaline displays a deep green color. Among them, blue and bright rose red tourmaline are of the highest quality. In the same tourmaline crystal, uneven distribution of components often leads to color changes, such as dual color tourmaline, multi-color tourmaline, or watermelon tourmaline with internal infrared green along the tourmaline.
Multi-color property
In addition to its rich and colorful colors, the most attractive feature of tourmaline is its multi color nature. When we hold tourmaline and rotate it against the light at different angles for observation, the color tone and depth of the tourmaline will change with different angles of observation. This is due to the strong multi-color nature of tourmaline, which also gives it a mysterious color. The piezoelectric and thermoelectric effects of tourmaline. When tourmaline is heated or subjected to pressure, or rubbed with silk or wool, electrode effects are generated at both ends of the columnar tourmaline, with one end being positively charged and the other end being negatively charged. This will cause tourmaline to attract some dust or small paper scraps, and this magical force is the piezoelectric and thermoelectric effects of tourmaline, which is also the origin of the name “tourmaline”. There was once an interesting story: Legend has it that in 1703, on a warm summer day in Amsterdam, the Netherlands, several children were playing with stones brought back by Dutch sailors. Suddenly, a child noticed that these stones were sucking up nearby dust and grass debris. The child was very surprised and asked their parents to come and see, and indeed found that this stone could attract or repel light objects such as dust and grass shavings. From then on, the Dutch called it a “smoke ash stone” and used it to clean the ash in cigarette pipes.
Tourmaline cat’s eye effect
The interior of tourmaline crystals contains abundant vapor-liquid inclusions, often distributed in a directional manner, forming tubular inclusions. The dense tubular inclusions can cause a cat’s eye effect on tourmaline processed into curved or spherical shapes – a clear bright band appears on the surface of the tourmaline, and the bright band changes with different observation angles.
varieties
By color
The composition of tourmaline is complex, and its color is also diverse and varied. The international jewelry industry generally divides tourmaline into commercial varieties based on color, with darker and more vibrant colors having higher value.
Indicolite: A general term for light blue to dark blue tourmaline. Blue tourmaline, due to its rarity, has become the most valuable color among tourmalines. Blue tourmaline is produced in the yellow clay of weathered granite in Siberia, Russia, and is also found in Brazil, Madagascar, and the United States.
Rubelite: A general term for pink to red tourmaline. Red is the best color for tourmaline, with purple red and rose red being the best. It is also known as red tourmaline and is referred to as “child’s face” in China. But in nature, there are more shades of brown, reddish brown, and deep red produced, with significant variations in color tones. Meanwhile, the specific gravity of tourmaline varies with color; The density of deep red is greater than that of pink.
Brown tourmaline: darker in color and rich in the chemical element magnesium. Brown tourmaline is mostly produced in Sri Lanka, three countries in North America, Brazil, and Australia. The English name for brown tourmaline comes from the Drewe region of Austria
Achroite: Achroite is extremely rare and is only produced in small quantities in Madagascar and California, USA. It should be noted that some colorless tourmalines on the market are made by heating and diluting pink tourmaline. The English name for colorless tourmaline comes from the ancient Greek word ‘achroos’, which means colorless
Green tourmaline: Green and yellow tourmalines are the most common color variations of all tourmalines, and therefore have lower value than blue and red tourmalines. Green tourmaline is commonly found in Brazil, Tanzania, and Namibia, while yellow tourmaline is distributed in Sri Lanka.
Multicolored tourmaline: Due to the well-developed color bands of tourmaline, red and green two-color or tricolor bands often appear on a single crystal. Common gemstones with red and green colors, commonly known as “Watermelon Tourmaline,” are highly favored by collectors and consumers.
Identification and differentiation
Crystal and tourmaline: mainly observe their colors. Generally speaking, purple is less common in crystals, while tourmaline’s purple is generally lighter, with shades of pink purple and light purple. On the other hand, crystals do not have the red and green colors like tourmaline (except for hair crystals), so the difference in color between the two can be used to roughly identify authenticity.
Fluorite and tourmaline: In terms of hardness, tourmaline has a Mohs hardness of 7.5 degrees, while fluorite has a hardness of only around 4 degrees on the Mohs scale. The two can be compared by scratching the glass. Secondly, when impersonating tourmaline, fluorite often uses materials with multiple colors, and tourmaline does not have purple. However, fluorite often has purple when multiple colors appear, so this is also an effective means of distinguishing between fluorite and tourmaline.
