Hobbies And Interests
Things You'll Need
Instructions
Determine the hardness of the stones you will be working with. You can do this by either checking the Internet or consulting a book on gemstones. For example, if you are working with quartz or agate you can type "hardness of agate" in a search engine and you will get accurate results.
Determine the hardness of the cutting wheel. This should be explicit on the tag of the wheel. Although there is not an industry standard in marking hardness, the latter letters of the alphabet mean the wheel is harder, while the initial letters mean the wheel is softer. If you are working with a hard stone, a letter such as V will cut better and last longer. An A or a B will be eaten up quickly by a hard stone such as a ruby.
Determine the grit. If you are working with a hard stone, a coarse 16 to 24 grit will be good to cut the basic shape. You will then want to gradually increase the grit as you give the stone more polish and character. You can go from 24 to 36 to 80 to 100+ for a total of four different grinding wheels before polishing. If you cut the stone with a 24-grit wheel, it will be full of nicks and will not take a good polish. If you are working with soft stone like malachite or turquoise, you could get away with making the rough cut with a 36 grit or even higher.
Determine the grit type. By far the most common and the most economical grit type for cutting gemstones is aluminum oxide. Some extremely hard stones may require an industrial diamond grit as the aluminum oxide may not be hard enough. However, this is just for corundum or higher.
Determine the grit color. The gray-colored grinding wheels are the most economical and the most resistant to relatively hard stones. If you want durability and a good price, gray is the best bet for lapidary purposes.