Obsidian has a hardness of 5 and a specific gravity of 2.35. It is used for carvings and jewelry. Sodalite is one of the mineral components of lapis lazuli . . Sodalite has a hardness of 5.5 to 6 and a specific gravity of 2.1 - 2.3. Sodalite is found in Brazil, Canada, India, Italy, Namibia, United States, and Russia.
Solders melt at a lower temperature than the metals to be joined.
Specific gravity measures the density of a material. The crystals are transparent to translucent. Spectrolite is usually cut with a flat surface in order to highlight the brilliant flashes of color. Spectrolite has a hardness of 6 to 6.5 and a specific gravity of 2.70. A spectroscope is an instrument that is used to identify gemstones .