Zhangqiu Granite

Characteristic of Zhangqiu Black

Mineral Composition

The ore is black, the ore structure is medium-fine gabbro structure, and the ore structure is mainly dense massive structure. The main minerals are plagioclase, ordinary pyroxene, perilla pyroxene and potassium feldspar, with a small amount of biotite and quartz; the secondary minerals are apatite and magnetite; and a very small amount of apatite. Secondary minerals are chlorite and amphibole.

Property of Zhangqiu Black

After polishing, the smooth surface of stone is grey-black. Nearly, the black and white dots are distinct, and the general appearance is gray, but mainly in black tone. The gray and black two kinds of clouds are intertwined in an orderly way, with rich and soft aesthetic feeling. Looking from a distance, the grey and black are symmetrical, and the dark green in the black gives people a luxurious and solemn feeling. The fine grains in the ore structure are very uniform, the rock is compact, hard, corrosion resistance is strong, compressive and flexural strength is high, water absorption and wear is very low. There are no cracks and speckles on the smooth surface. Block size is relatively complete. Both internal and external exposures meet the requirements of Class A products.

Key Points of Material Selection

1. High hardness 2. Low water absorption 3. High relative density (high specific gravity) 4. Low porosity 5. High compressive strength 6. High Tensile Strength 7). Large damage modulus 8. Low acid solubility 9. Low coefficient of thermal expansion 10. Good frost resistance 11. Low abrasion 12. High shear strength 13. Small Elastic Deformation

Physical Test of Zhangqiu Black

Report of Jinan Mineral Resources Supervision and Detection Center of Ministry of Land and Resources
The physical parameters of Zhangqiu black granite meets the requirements of national standard granite surface plate

 Chemical Composition

According to the Detailed Investigation Report, the average chemical composition of the two samples was as follows.

Chemical composition






















 Processing characteristics

1. The processing characteristics of Zhangqiu Black are as follows: fewer cracks in stone, higher rate of discharging material and faster discharging material; easy-to-cut planer and high efficiency of machining; high water absorption rate of grinding and doubling of stabilization time; shorter processing period of comprehensive practice than Jinan Black by 2-3 days.

2. The grinding accuracy of Zhangqiu Black: Because of its high water absorption, sinking while grinding, the grinding sinking of coarse sand obviously needs to be stabilized for a long time before testing, and the grinding of fine sand is not obvious, so it must have sufficient stable time to evaporate water, which is double the time of Jinan Black, and the precision changes little after stabilization.

3. The grinding roughness of Zhangqiu Black: from coarse sand to fine sand, grinding without sand barrier in turn, after finishing 600, the average strip roughness can reach 1.0 within 1.2; the average plate roughness within 1.5 is 1.2;

4. Slag Removal after Grinding Zhangqiu Black: Test of Slag Removal from Adhesive Belt: Preliminary Test 0.596 - - - Post-test 1.489 0.848

Compared with Jinan Black plate, especially black-dot mica, it affects the roughness. As for how to deal with it, we should have a way to infiltrate and grind with glue.

5. Protection in Zhangqiu Black Processing: It is easy to collapse and penetrate, so it is necessary to chamfer first and then hoist with wooden pad, generally C5; use dry pad or rubber pad to prevent imprinting; avoid oil pollution and easy penetration.



 Processing cases

Dimensions of processed products: 4600*350*250mm

Precision of the front (4600x350):


Dimensions of processed products: 4600*350*250mm

Recheck of front (4600x350) precision with laser interferometer