The finest whiting for making brilliant white chalk grounds. Our whiting is dry ground from limestone deposits in the Lucerne Valley, California. Dry grinding limestone reduces it to a powder without destroying its particle structure, which is important in making strong chalk grounds and providing tooth on the surface of the grounds. The larger particle size of our chalk (when compared to precipitated chalk) keeps oil absorption low, which is ideal when adding it to oil paint and mediums. In painting grounds, it makes a durable surface with tooth for egg and casein tempera, distemper, encaustic, and oil paint.
Add to oil colors and mediums to create textural and bodying qualities to oil paint without affecting the color. Chalk has a little color in drying oil, so it can be added to oil paint without affecting the tint of the color.
| Properties | ||
| Dry ground limestone with a closely-controlled particle size distribution. | ||
| Source | Lucerne Valley, California | |
| Chemical Name | Calcium Carbonate | |
| Chemical Formula | CaCO3 | |
| CAS No. | 13397-26-7 | |
| Typical Physical Properties | Fine | Extra-Fine |
| Median Particle Size | 13.0 microns | 3.5 microns |
| Dry Brightness (Hunter Y, Rd Value) | 95 | 96 |
| Retained on 325 Mesh Screen | 0.001% | 0.1% |
| Oil Absorption | 8.5 g oil / 100 g pigment | 10.5 g oil / 100 g pigment |
| Loose Bulk Density | 0.69 g/cc (43 lbs./ft3) | 0.46 g/cc (29 lbs./ft3) |
| Packed Bulk Density | 1.63 g/cc (102 lbs./ft3) | 1.14 g/cc (71 lbs./ft3) |
| Specific Gravity | 2.7 | 2.7 |
| Mohs Hardness | 2–3 | 2–3 |
| Typical Chemical Analysis | ||
| Calcium Carbonate (CaCO3) | 98.5% | |
| Magnesium Carbonate (MCO3) | 1.0% | |
| Iron Oxide (Fe2O3) | ||
| Moisture Loss @110° C. | ||