What is Aventurescence?

Aventurescence: An Optical Reflectance

Aventurescence is a captivating optical effect found in certain minerals and gemstones. Best known in aventurine, it's often described as a sparkling or glittering appearance caused by minute, plate-like inclusions.

When present in abundance, the inclusions can influence the stone's colour.

As light reflects off metallic inclusions within the stone, a spangled reflection can be seen. This optical phenomenon is aventurescence.

Although best known for its presence in aventurine, aventurescence can also be seen in sunstone.  

In sunstone, also known as aventurine feldspar, the effect is caused as light reflects off minute inclusions of copper.

The word 'aventurescence' is widely reported to have come from the Italian "a ventura," meaning "by chance." This is said to have come about following the 'chance discovery' by Italian monks of aventurine glass, also known as goldstone.

Depending on the article you read, the occurrence is said to have taken place in the 13th, 17th, 18th or 19th century.  

There is no factual evidence to support this event.  

The story claims that Venetian glass-making monks accidentally dropped a jar of copper specks into a vat of molten glass. Once the mixture cooled and solidified, it had a spangled or glittery appearance.

The material is said to have been named aventurine glass because it was discovered 'by chance.'

According to factual historical documentation, aventurine glass (goldstone) is believed to have been created by Italian physicist and astronomer Vincenzo Miotti.

The mineral aventurine, also known as aventurine quartz and aventurine feldspar (sunstone), are likely to have been named after aventurine glass because they exhibit aventurescence.