Aventurine is a variety of Quartz

A variety of Quartz containing shiny fragments (usually mica), which can be cut and polished as a gemstone.

Aventurine is a form of quartz, characterised by its transparency and the attendance of platy mineral inclusions that give a iridescent or glistening effect termed aventurescence.

Aventurine feldspar or sunstone can be mystified with orange and red aventurine quartzite, although the former is normally of a higher transparency. Aventurine is often banded and an excess of fuchsite may render it opaque, in which case it may be mistaken for malachite at first glance.

The name aventurine derives from the Italian "a Ventura," meaning "by chance." This is a reference to the chance discovery of aventurine glass or goldstone at some point in the 18th century. Even though it was known first, goldstone is now a common imitation of aventurine and sunstone. Goldstone is well-known visually from the latter two minerals by its coarse platelets of copper, dispersed within the glass in an unnaturally uniform manner. It is usually a golden brown, but may be stained blue to create "bluestone."

The greater part of green and blue-green aventurine originates in India (particularly in the surrounding area of Mysore and Madras) where it is employed by prolific artisans. Creamy white, grey and orange material is found in Chile, Spain and Russia. Most material is carved into beads and figurines with only the finer examples fashioned into cabochons, later being set into jewellery.
Main markets for aventurine are landscape stone, building stone, aquarium, monuments, and jewellery.
Aventurine is often referred to as the all-purpose healer. This means not only that it is considered by many to be good for physical disorders, but that it heals on all levels. Green is the colour of healing, and aventurine, as a member of the quartz family, has a intense ability to dissolve blockages.

It's a predominantly effective crystal for emotional healing (and is especially obliging when worn for this purpose or placed on the heart center during charka balancing). It helps to balance the emotions, and is one of the best stones to wear or carry during stressful periods.