Spheres

Spheres

Many sizes and qualitites.

We carry considerable variety of stone spheres made from various natural minerals and rocks of different sizes. They range in size from the size of marbles up to perhaps 10 inches in diameter, but most of them are not more than 6 inches in diameter. Many of them range in price from $40 to $80 a pound though some are more depending on the quality. Exceptional ones can run more and sometimes much more per pound.

The cost ranges from $15 per pound up to more than $100 per pound. Almost always the cost is proportional to the quality of the stone they are made from and the size of the sphere. The larger the sphere, the more it costs. The cost of a sphere depends more or less on its weight and since the volume of a sphere and it weight goes up at the cube of its square of its radius, a sphere of ten inches diameter will cost much more than double the cost of one five inches in diameter.

The formula for calculating the volume of a sphere is where r = the radius of the sphere. If the units you are using are cubic cm then to find the weight of the sphere you will need to multiply the volume of your sphere by the specific gravity of the material the sphere is made from. In the case of quartz you would need to multiply the volume of the sphere in cubic centimeters by 2.65 grams per centimeter.

For example, the weight of a quartz family mineral like rose quartz, or agate that is 2 inches in diameter will weigh about .4 pounds and one that is 4 inches in diameter will weight about 3.2 pounds. If the cost of such a typical sphere is $40 per pound, then a two inch sphere of quartz would cost about $16 and that of a 4 inch sphere about $129.

Also keep in mind that the density of various minerals and rocks can vary substantially and this means that a two inch sphere made from pyrite will weigh nearly twice what a sphere made from quartz will weigh. Spheres are interesting because they represent the shape of most planets and one of the classical Platonic three dimensional geometrical solids and it is manipulated mathematically. When you make a sphere out of a rough mineral or stone it also shows the nature of the material from all angles as you rotate it. They are popular with some collectors and of course we all know that we would like to gaze into a crystal ball and see the future.

The classical crystal balls are made from quartz, and we carry some of those, but we rarely ever have one that is completely clear. Often “crystal balls” are made from glass, and these can be inexpensive. Sometimes customers come to us and want an absolutely “crystal clear” crystal ball seven or eight or more inches in diameter. I usually ask them in return: “Wouldn’t you rather have a new house?”. Crystal to us means quartz crystal and not glass crystal

Amethyst Spheres