Knowledge
What is Jade?
Jade is a mineral primarily divided into two types: jadeite and nephrite.
Jadeite, rated 6.5 to 7 on the Mohs scale, is composed of sodium aluminum silicate (NaAlSi2O6) and forms under high-pressure, low-temperature conditions. The largest deposits are found in Myanmar, with smaller amounts sourced from Guatemala, Japan, the United States, and Russia.
Nephrite, with a hardness of 6.0 to 6.5, consists of calcium magnesium silicate (Ca2Mg5(OH)2(Si4O11)2). It typically forms in low-pressure metamorphic rocks and is highly valued in such as China, particularly from the Hotan region in Xinjiang for its purity.
Quality
Jadeite quality is assessed based on four key aspects:
1. Color: A crucial determinant of value, with desirable shades enhancing appeal.
2. Transparency: High-quality jadeite displays great transparency and a fine texture.
3. Shape: Consistency in shape, size, and uniform thickness is essential.
4. Impurities: The absence of spots, cracks, and other flaws is vital for superior quality.
Type A, B, C
Jadeite is usually identified by the type A, B, and C in the market to identify the texture of jade products:
Type A, is a natural jadeite that has not been chemically treated and has a natural color and effect.
Type B, is jadeite that has been cleaned and injected with glue in strong acid. Strong acid soaking and cleaning can help improve the transparency and color of jadeite.
Type C, is jadeite that has been artificially colored, usually with organic dyes or inorganic dyes.
Type B+C, is jade that has been treated with strong acid cleaning, glue injection and artificial coloring at the same time.
Species
The "species" of jadeite refers to a comprehensive evaluation based on transparency and texture (granularity). It is classified into five types: bean, waxy, ice glutinous, ice, and glass species.
These species vary in transparency, with increasing clarity, while all exhibit fine, uniform granularity. Factors such as texture visibility, particle tightness, and the presence of cotton threads further influence each species' quality.
Color
The understanding of jadeite's color revolves around four key aspects: purity, brightness, saturation, and uniformity.
1. Colorless: Transparent or translucent, resembling ice or glass, symbolizing perfection and purity.
2. White: Milky appearance due to coarse particles, affecting its transparency.
3. Green: Ranges from youthful bean green to noble imperial green, including variations like blue aqua green and ink green.
4. Purple: Vibrant hues varying from reddish to blue, appealing to collectors.
5. Black: Pure black tones with varying shades, adding depth and richness.
6. Yellow and Red: Historically significant shades, once more valued than green.
7. Combination: Pieces featuring multiple colors, prized for their rarity and distinctiveness.
Transparency
Determining jadeite's transparency involves examining its internal structure. Finer crystals allow light to penetrate more smoothly, enhancing transparency.
Sunlight Test: For raw jadeite, observe how deeply sunlight penetrates the stone. The visibility of light through the jade indicates its transparency.
Halo Measurement: Gemologists often use a halo measurement system, evaluating light transmission through jade at various thicknesses.
Several factors influence jade's transparency, including mineral structure, depth of color, and thickness of the jade material.
Maintenance
To preserve its luster and prevent damage, jadeite jewelry requires careful handling.
When wearing, avoid collisions and friction by storing each piece separately and rinsing with cold water after use to remove sweat. Clean quickly with warm soapy water, then gently wipe with alcohol and allow to air dry away from direct sunlight.
When not in use, rinse the jadeite with cold water and soak it for a few hours to maintain moisture. Keep it away from heat sources and prolonged sunlight exposure to ensure its longevity.