1. Hardness:  Black SiC is around a Mohs 9.1 or 2550 Knoop.  Green SiC is harder than black, coming in at a 9.4 Mohs and 2600 on the Knoop scale.
2. Purity:  Black will range in purity from 97-99% pure, depending on grit size.  Green is generally ~99.5% pure.  Black SiC will contain some free silicon and carbon and thus is not as pure as green SiC.
3. Pricing:  Unless your application requires an extremely pure SiC, by default, black is preferred due to its more economic pricing.
4. Why is it Green?  The non-technical answer is this: When they make Black Silicon Carbide, the Green Silicon Carbide is in the
   center of the ingot and is more pure, which causes it to be Green in color.

Green Silicon Carbides:

• Thermal Conductivity: High (100 W/m-K) approximately
• Gradation:  Generally FEPA grade, coarse grade meet both ANSI & FEPA
• Incompatabilities: None
• Melting Point: 2723 ?F
• Typical Packaging: 500 kg bags
• Odor: Odorless
• Safety: Avoid breathing dust; wear protective gear
• Purity: 99% approximate
• Friability: Semi-Friable
• Pricing Based Per: Pound
• Structure: Monocrystalline
• Shipping Point: Chicago
• NMF Classification: Class 55
• Fire & Explosion: Fines can cause explosion and smolder
• Keep away from all sources of ignition
• Color: Green
• Hardness: Knoop 2600 (Green SiC)
• Instability: Stable
• Hazardous? Not listed as hazardous; see other cautions
• Disposal: According to Federal, State, Local regulations
• Grain Shape: Blocky, sharp edged
• Type: Granular or powdery depending on grade
• Specific Gravity: 3.2 (SiC)
• Bulk Density: ANSI B74.12-198

Typical Applications:

• Lapping
• Polishing
• Slurry Mixes
• Super-Refractory Applications
• Wire Saw Slicing
• Sintering
• Thermal Conductivity
• Green is often the media of choice when it comes to wire sawing (JIS 800, JIS 1000, JIS 1200, JIS 1500)

Particle Size distribution for available grits:
Grading: FEPA Standard

 Note: JIS and P Standard graded powder is available on request, given sufficient volume is met.