Chalcedony to as prase. However, the term prase is also used to describe green quartz, and to a certain extent is a color-descriptor, rather than a rigorously defined mineral variety.) Blue-colored chalcedony is sometimes referred to as "blue chrysoprase" if the color is sufficiently rich, though it derives its color from the presence of copper and is largely unrelated to nickel-bearing chrysoprase. Heliotrope is a green variety of chalcedony, containing red inclusions of iron oxide that resemble drops of blood, giving heliotrope its alternative name of bloodstone. In a similar variety, the spots are yellow instead, known as plasma. Moss agate
Mineral evolution surrounding molecular cloud. 60 new minerals were produced and were preserved as inclusions in chondrites. The accretion of dust into asteroids and planets, bombardments, heating and reactions with water raised the number to 250. Before 4.56 Ga, the presolar nebula was a dense molecular cloud consisting of hydrogen and helium gas with dispersed dust grains. When the Sun ignited and entered its T-Tauri phase, it melted nearby dust grains. Some of the melt droplets were incorporated into chondrites as small spherical objects called chondrules. Almost all chondrites also contain calcium–aluminium-rich inclusions (CAIs), the earliest materials formed in the Solar System.