Mourning ring
Definition and Purpose of Mourning Rings Finger ring worn in memory of someone who has died Bears name, date of death, and possibly an image or motto Usually paid for...
Glossary
Morganite (gem)
Name and Characteristics Morganite named after J. P. Morgan in 1911. Also known as pink beryl, rose beryl, pink emerald, and cesian beryl. Pink color attributed to Mn ions. Pleochroic;...
Moonstone (gemstone)
Etymology and Physical Characteristics Moonstone derives its name from the stones characteristic visual effect called adularescence or schiller. Adularescence produces a milky, bluish interior light caused by light diffraction through...
Moissanite
Background and Discovery of Moissanite Moissanite was discovered by Henri Moissan in 1893 while examining rock samples from a meteor crater in Arizona. Initially mistaken for diamonds, the crystals were...
Mohs scale
Mohs Scale of Mineral Hardness Developed by Friedrich Mohs in 1812 Measures the hardness of minerals based on their ability to scratch each other Consists of 10 minerals ranked from...
Mineralogy
History and Advances in Mineralogy Early writing on mineralogy comes from ancient Babylonia, the ancient Greco-Roman world, ancient and medieval China, and Sanskrit texts from ancient India and the ancient...
Miller index
Miller Indices and Crystallography Miller indices are a notation system used in crystallography. They represent lattice planes in crystal lattices. Negative integers are denoted with a bar. Miller indices can...
Middle finger
Anatomy of the Middle Finger The middle finger is the third digit of the human hand. It is located between the index finger and the ring finger. In anatomy, it...
Metalworking
Historical Development of Metalworking Oldest evidence of metalworking found in northern Iraq from 8,700 BCE Metalworking in the Americas dates back to 4000-5000 BCE in Wisconsin Oldest gold artifacts date...