SAFIIRI 4,5mm , kuvallisella aitoustodistuksella
pyöreä briljantti hiottu luonnollinen sini SAFIIRI 4,8mm hyväsininen ruiskukan sävy , aitoustodistus
Safiiri / Sapphire , kuvallisella aitoustodistuksella
Huomioita: ruiskukan kirkas sininen sävy ja hyvä viiste hiontainen luonnollinen safiiri yksilö kuvallisella aitoustodistuksella
Subtle differences in color correspond to marked variations in price valuations. Fine stones of good color and clarity are always rare and uncommon. The best and most valuable colors for blue sapphires are actually violetish blue. Highly saturated medium or dark medium tones are best and sapphires which are too dark or too light are worth considerably less.
Sapphires and rubies are both members of the corundum family with the same hexagonal crystallographic structure. The basic chemical formula is AL2O3 .. the same for both ruby and sapphire. It is the presence of trace elements like chromium, iron, vanadium and titanium which are responsible for the wide range of colors in which the mineral occurs. When a corundum is red, it is known as a ruby and any other color is a sapphire. In practice however, the determination is not always so straightforward because there are no internationally accepted standards for the color of a ruby. Gemologists could describe the same stone as a purplish red ruby or a purplish red sapphire and borderline cases are not uncommon.
Sapphires are noted for the large range of colors in which they occur. The name fancy sapphire, is used to describe sapphires which are not blue. Fancy sapphires are available in an amazing range of colors including yellow, green, violet, pink, brown, purple, violet, white, black and orange.
Occurrences: The most notable deposits of Sapphire are located in Burma, Australia, East Africa, Sri Lanka, and Madagascar. Other well known deposits include Montana, USA; and Kashmir, India. The deposit in Kashmir is no longer producing and the deposits in Montana may not produce enough to be commercially viable.
The Source: Many of the important sapphire deposits in Sri Lanka, Madagascar, Kenya and Tanzania are geologically related to each other. Australia, Antarctica, Sri Lanka, Madagascar and Africa were all connected in a super continent known as Pangaea billions of years ago. Giant rivers carried gemstones from the same source and deposited them throughout this super continent as alluvial gravels. Between 200 to 400 million years ago, the continents began to separate as a result of tectonic forces and continental drift.
The same stones from the original deposit are now found in Sri Lanka, Madagascar, and Tanzania. Sri Lanka was probably closest to the source and we know this because the stones there are larger with better crystallization. As the stones were carried to what is now Madagascar and Tanzania, they would have became smaller and more rounded because of the longer distance they traveled. The largest stones are in Sri Lanka. South Madagascar and Tunduru, rough is generally smaller with less defined crystallization. The concentrations and colors of the gravels show remarkable similarity across this huge deposit.
The stones from these localities are extremely difficult or impossible to differentiate. To further complicate the geology, indigenous sapphires with more localized source rocks are also found in nearby areas.Sri Lanka: is well known for the fine quality and broad range of colors of the