砂金效应是宝石学中在某些宝石中看见的光学反射效应。这种效应取决于矿物内无机物小片的方向，在瞬间产生造成金属的光泽。这种小片太多时也会影响到物体的色泽。在耀石英（星彩石英，实际上是一种石英）铬影响铬云母的绿色石头，各种氧化铁使石头呈现红色。

aventurine和aventurescence是从意大利文的"a ventura"引申出来的，意味着"偶然"。这是暗指18世纪发现金斑玻璃或砂金石是很偶然的。在发现耀石英和日长石之后，迄今砂金石仍以人工仿制生产。因为参杂有"硫酸铜"，砂金石有时会有淡淡的蓝色。

In gemology, aventurescence (sometimes called aventurization) is an optical reflectance effect seen in certain gems. The effect amounts to a metallic glitter, arising from minute, preferentially oriented mineral platelets within the material. These platelets are so numerous that they also influence the material's body colour. In aventurine quartz chrome-bearing fuchsite produces a green stone, and various iron oxides produces a red stone.