Goldstone

Size is a decisive factor affecting the price of goldstone. The price of a stone about 2.5 cm across is usually $1-$7/piece.

The poor toughness of goldstone can be attributed to its glassy matrix, characterized by the absence of a crystalline structure and inherent internal stresses, rendering it susceptible to chipping and cracking upon impact.

Goldstone demonstrates stability under most daily use conditions except when exposed to extreme heat or harsh chemicals.

Copper colloid size and failure modes

Copper-based "red goldstone" aventurine glass exists on a structural continuum with transparent red copper ruby glass and opaque "sealing wax" purpurin glass, all of which are striking glasses, the reddish colors of which are created by colloidal copper. The key variable is controlling the colloid size: goldstone has macroscopic reflective crystals; purpurin glass has microscopic opaque particles; copper ruby glass has submicroscopic transparent nanoparticles.

The outer layers of a goldstone batch tend to have duller colors and a lower degree of glittery aventurescence. This can be caused by poor crystallization, which simultaneously decreases the size of reflective crystals and opacifies the surrounding glass with non reflective particles. It can also be caused by partial oxidation of the copper, causing it to redissolve and form its usual transparent blue-green glass in ionic solution.

When reheated for lamp-working and similar uses, the working conditions should control the temperature and oxidation as required for the original batch melt: keep the temperature below the melting point of copper (1084.62 °C) and use an oxygen-poor reducing flame, or risk decomposition into the failure modes described above.

Non-copper goldstones

Goldstone also exists in other color variants based on other elements. Cobalt or manganese can be substituted for copper; the resulting crystals have a more silvery appearance and are suspended in a strongly colored matrix of the corresponding ionic color, resulting in blue goldstone or purple goldstone respectively.

Green goldstone, or chrome aventurine, forms its reflective particles from chromium oxides rather than the elemental metal, but is otherwise fairly similar.

The non-copper goldstones are easier to work with when reheated, due to the less stringent reduction requirements and higher melting points of manganese (1246 °C) and cobalt (1495 °C).

The most common form of goldstone is reddish-brown, containing tiny crystals of metallic copper that require special conditions to form properly. The initial batch is melted together from silica, copper oxide, and other metal oxides to chemically reduce the copper ions to elemental copper. The vat is then sealed off from the air and maintained within a narrow temperature range, keeping the glass hot enough to remain liquid while allowing metallic crystals to precipitate from solution without melting or oxidizing. After a suitable crystallization period, the entire batch is cooled to a single solid mass, which is then broken out of the vat for selection and shaping. The final appearance of each batch is highly variable and heterogenous. The best material is near the center or "heart" of the mass, ideally with large, bright metal crystals suspended in a semitransparent glass matrix.

Goldstone is a man-made form of glass that refracts light to produce an attractive glittering effect. This property makes it a valuable decorative glass used for jewelry, beads, and other decoration. This glass was manufactured in Venice as long ago as the 17th century to a technique formulated by the Miotti family.

Goldstone has been known to humans for thousands of years and many legends and beliefs are associated with it. It has been linked to the art of alchemy and according to an interesting (but probably fictional) story, the stone was accidentally made by the Italian monks in the 17th century in an attempt to make gold.

Another common name for the material is aventurine glass, based on the original Italian name avventurina (from avventura, "adventure" or "chance"). It is called "del-roba" (Persian: دلربا) in Persian which means "Charming"; or "monk's gold" or "monkstone" from folkloric associations with an unnamed monastic order. Additionally, "aventurine" glass is one of the few synthetic simulants to provide the eponym for the similar natural stones. The mineral name "aventurine" is used for forms of feldspar or quartz with mica inclusions that give a similar glittering appearance; the technical term for this optical phenomenon, "aventurescence", is also derived from the same source.

Goldstone is often referred to as the stone of ambition that helps a person achieve their goals. It may allow one to see past any obstacles in their way to success and encourages focus and determination. It works on the Root chakra to transmit positive energy throughout the body and to block negative energy from interfering with one's aspirations.