1 Hardness: cubic zirconia has a rating of approximately 8 on Mohs hardness scale vs. a rating of 10 for diamond. 2  Specific gravity: the density of cubic zirconia is about 1.7 times that of diamond. 3  Refractive index: cubic zirconia has a refractive index of 2.15â2.18, compared to a diamond's 2.42.he synthesized material is hard, optically flawless and usually colorless, but may be made in a variety of different colors. It should not be confused with zircon, which is a zirconium silicate (ZrSiO 4).
When GPS service was first made available for civilians in 1983, for national security reasons, the U.S. military decided to scramble the signal, making it a little too inaccurate to be reliable. This practice, also known as selective availability, was aimed at preventing military use of GPS by the enemies.
The Selective Service System created by the 1940 Act was terminated by the Act of March 31, 1947. 1948 to 1969. The Selective Service Act of 1948, enacted in June of that year, created a new and separate system, the basis for the modern system. All men 18 years and older had to register with Selective Service. All men between the ages of 19 to 26 were eligible to be drafted for a service requirement of 21 months.