Green Silicon Carbide Micropowder for Jadeite Polishing
Green Silicon Carbide Micropowder for Jadeite Polishing
I. Advantages of Green Silicon Carbide for Jadeite Polishing
Jadeite has a Mohs hardness of 6.5–7, while green silicon carbide (GC) boasts a Mohs hardness of 9.4–9.5. It features matched hardness and excellent self-sharpening property, serving as the mainstream abrasive for rough & medium grinding to fine pre-polishing by jade vibration tumblers and manual polishing machines. Diamond powder or chromium oxide is adopted for final mirror finishing.
- High cutting efficiency: Sharp-edged particles rapidly eliminate carving marks, pits and coarse scratches. It rarely clogs stone surfaces and generates little heat to prevent scorching jadeite.
- Uniform and fine particle size: High-purity water-washed classified powder delivers consistent surface textures without uneven scratches of varying depths.
- Chemical inertness: It does not react with jadeite minerals, resulting in no corrosion or color staining. Safe for ice jadeite, flower-pattern jadeite, white-base jadeite and all other varieties.
- Higher cost performance than diamond powder: Green silicon carbide can be used throughout rough and medium grinding procedures to greatly cut polishing material costs, while diamond powder is only applied in small doses for final mirror polishing.
- Difference from black silicon carbide: Green silicon carbide has higher purity, better brittleness and finer cutting performance. Black silicon carbide contains excessive impurities, only suitable for rough shaping of stone materials and not recommended for fine jade polishing.
II. Matching Grit Sizes for All Jadeite Polishing Processes (Mesh / W Micron Standard Comparison)
1. Rough Grinding (Shaping & Mark Removal, Vibration Tumbler / Hanging Grinder)
- 240# / W63: Quickly level bulk blanks with deep carving marks and uneven surfaces
- 400# / W40: Remove deep scratches from rough grinding and complete basic surface leveling
2. Medium Grinding (Transition Sanding, Most Widely Used)
- 600# / W28: Eliminate extensive fine scratches to form a matte base surface
- 800# / W20: Standard medium polishing grit for mass production with vibration tumblers
3. Fine Pre-Polishing (Preliminary Step for Mirror Finish, Determines Base Smoothness)
- 1200# / W14
- 1500# / W10
- 2000# / W7 (equivalent to 2500#): Fine pre-polishing for high-grade jadeite, leaving nearly invisible scratches
4. Superfine Micropowder (Pre-Finishing for Small Cabochons & Oval Jade Faces)
Available grits: 3000#, 4000#, 6000#, 8000#, 10000#. These powders only form an ultra-smooth base and cannot achieve mirror gloss independently; final finishing with diamond powder is mandatory.
III. Two Mainstream Polishing Processes
1. Vibration Tumbler Polishing (Mass Processing of Bangles, Pendants & Jade Beads)
Mixing formula: Water + green silicon carbide micropowder + abrasive media (bamboo cores, plastic grinding pellets)
Process flow: Gradually upgrade grit size in sequence of 240# → 400# → 800# → 1200# → 2000#. The tumbler must be thoroughly cleaned before switching to finer grits, as residual coarse particles will leave permanent deep scratches on jadeite.
2. Manual Polishing with Hanging / Horizontal Grinders (Cabochons, Patterned Ornaments & 3D Carvings)
- Grinding wheels / oil stones: 240#–800# green silicon carbide oil stones for rough shaping
- Loose abrasive polishing: Mix 1200#–3000# micropowder with water, polish preliminarily with bamboo strips, rubber wheels and leather wheels
- Final finishing: W1.5/W2.5 diamond powder matched with leather discs to form mirror gloss
IV. Division of Labor Between Green Silicon Carbide and Diamond Powder (Standard Matching for Jadeite Polishing Industry)
- Green silicon carbide micropowder: Completes all rough, medium and fine pre-polishing work, removes 99% of carving marks and scratches to create a flat base surface.
- Diamond micropowder: Only used for final mirror polishing. Low consumption with high cost, solely for boosting glass-like luster.
- Chromium oxide polishing powder: Mainly applied for fast brightening of jade beads and low-grade jade products, inferior to diamond powder in fineness.
V. Core Selection Indicators for Procurement (Factory Supply Standards)
- SiC purity ≥98.5%: Low impurity content to avoid black spots and pitting on jadeite surfaces.
- Water-washed classified powder: Narrow particle size distribution free of oversized impurity particles to prevent scratches on high-value jadeite.
- Two available standards:
National standard mesh sizes (60–10000#): Universally applicable to domestic vibration tumblers
W micropowder grades (W63–W1.5): Specially for precision mechanical polishing and cabochon processing
- Packaging: 25kg woven bags ; anti-caking treatment for superfine powder dedicated to wet polishing
