绿玉髓，中国民间俗称绿玛瑙，(但严格说来，矿物学上仅把带状条纹的玉髓称为玛瑙，其他非条纹状的均不称做玛瑙)，英文单词chrysoprase来自希腊语“chrysos”和“prason”，意思是黄金和韭菜。 玉髓类中以蓝色最为稀少，绿色次之，而蓝色、绿色及紫色的玉髓，宝石界归为有价值的宝石，市场上其中绿色玉髓的外表易与翡翠混淆。

祖母绿或翡翠绿的颜色中的绿玉髓含有铬，所以呈现漂亮的翠绿色，故矿物学称做为铬绿玉髓；而苹果绿的颜色的绿玉髓是因为含有镍，故矿物学称做为镍绿玉髓。 矿物学分类中，玉髓的矿物成分为石英和斜硅石，且属于透明度较高且颜色均匀的隐晶质石英，若为不透明的隐晶质石英，矿物学称之为碧玉，另外倘若带纹理的条纹则矿物学称之为玛瑙。玉髓因为不同的成分元素，像是铁、镍、铬等会产生不同颜色。

Chrysoprase, chrysophrase or chrysoprasus is a gemstone variety of chalcedony (a cryptocrystalline form of silica) that contains small quantities of nickel. Its color is normally apple-green, but varies to deep green. The darker varieties of chrysoprase are also referred to as prase. (However, the term prase is also used to describe chlorite-included quartz, and to a certain extent is a color-descriptor, rather than a rigorously defined mineral variety.)