1 Dehydration. 2  Not staying hydrated with enough water during the day may be one of the big causes of leg cramps at night. 3  This is most likely due to fluid imbalances of electrolytes (mainly sodium, potassium, calcium, and magnesium).4  Overuse of the muscles, perhaps from exercising, gardening or other physical activities. Dehydration. 2  Not staying hydrated with enough water during the day may be one of the big causes of leg cramps at night. 3  This is most likely due to fluid imbalances of electrolytes (mainly sodium, potassium, calcium, and magnesium).
Lustre (mineralogy) Lustre or luster is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the latin lux, meaning light, and generally implies radiance, gloss, or brilliance. A range of terms are used to describe lustre, such as earthy, metallic, greasy, and silky. Similarly, the term vitreous (derived from the Latin for glass, vitrum) refers to a glassy lustre. A list of these terms is given below. Lustre varies over a wide continuum, and so there are no rigid boundaries between the different types of lustre.
Luster is the way a surface reflects light. Luster appears in minerals like when minerals are shiny or dull looking. When you say that you mean the way light reflects off the surface. Minerals can have metallic, submetallic, and nonmetallic luster. If a mineral were dull its luster would either be a submetallic or a nonmetallic luster. But if a mineral were shiny its luster would be metallic. Opals luster is a greasy looking reflection. Itâs not quite shiny but it has a greasy looking luster. In order to find a mineralâs streak what you do is the mineral has to be rubbed against a piece of unglazed porcelain or streak plate. When you do this the powder from the mineral ends up on the streak plate.