Jade, Stone of “Gods”: Terms, Concepts & Certification
Jade, for thousands of years a mythical stone appreciated in the Far East and in the high cultures of Native Americans, is rising high at present as it is sought after at auctions in Hong Kong and elsewhere. However, the term “jade” is quite vaguely defined. Different concepts try to describe the term based
ကျောက်မျက်များ၏ရောင်ကွဲများ နှင့် ၎င်းတို့ကိုဘယ်လိုခွဲခြားသတ်မှတ်မလဲ။
ကျောက်မျက်ရတနာဆိုသည်မှာ သဘာဝအတိုင်းဖြစ်ပေါ်လာတဲ့ တွင်းထ […]
เกณฑ์การเทียบสีและการกำหนดชื่อเฉพาะของอัญมณี
พลอย อัญมณี หรือรัตนชาติ ส่วนใหญ่เป็นแร่ ซึ่งเป็น […]
The Usambara Effect and other colour-change Effects in Gemstones
Colour change in gemstones is an interesting phenomenon, which can be due to a number of reasons. One of the causes is the so called Usambara effect, a type of colour change which is not so well known in the public. In contrast to the alexandrite effect, this phenomenon is not dependent on the type of illuminat
Fake Historic Provenance: ‘Aged ’ Cultured Pearls
Most recently, we received a pearl necklace with 410 pearls strung on three regularly graduated strands. The pearls were characterized by a beautifully matching colour and a fine pearl lustre, reminiscent of ‘classic’ natural pearls from the Arabian Gulf. However, a closer look using X-ray luminescence (SSE
Historic Sapphire of Catherine the Great
SSEF had the pleasure to add to this eclectic (data) collection the famous sapphire of Catherine the Great, a historic gem from Ceylon (Sri Lanka) of exceptional quality and beauty.
The Detection of HPHT-treatment of Diamonds at SSEF: 20 Years later
In 2000, SSEF announced that it was able to identify the HPHT treatment of type II diamonds. About 20 years later, this article summarizes how we were able to achieve this breakthrough and which people from the trade and other research institutions were involved in this important step.
批量合成鑽石中混入天然鑽石對鑑定造成的困擾
現今的鑽石交易中，大批量的天然鑽石中混有合成鑽石的情況因時有發生而倍受關注，然而我們在這裡提到天然鑽石被混入批量合成鑽石中的情況雖與常情相反但也值得引起注意，這在不久的將來可能會成為鑽石交易中一個（故意製造？
Fake Tridacna Pearls
Fake pearls are beads (of whatever shape) which have been cut entirely from shell material. A perfect source for the production of such fake pearls is the Tridacna clam, amongst the largest living bivalve mollusc with a massive and thick shell of up to 110 cm diameter, mainly living along shallow coastal water