Gemological gemstone appraisal for diamonds, rubies, sapphires, emeralds and other colored gemstones
Would you like to have your valuable gemstones valued?
Gemstones have fascinated mankind for thousands of years.
Their dazzling colors and rarities have made them symbols of power and wealth. Even in ancient cultures, diamonds, rubies, sapphires and emeralds were coveted and adorned kings or served as talismans. Even today, gemstones have lost none of their appeal. Their value is determined by their quality, rarity and cut.
In addition to the well-known colored gemstones and diamonds, the Gemmological Laboratory Austria also offers other gemstones and their varieties – such as tourmaline (rubellite, indigolite, verdelite), topaz (imperial topaz), beryl (aquamarine, morganite, gold beryl, heliodor, goshenite), garnet (demantoid, tsavolite, spessartine, mandarin garnet, hessonite, rhodolite, pyrope), zoisite (tanzanite), chrysoberyl (alexandrite), spodumene (hiddenite, kunzite), olivine (peridot), spinel, zircon and quartz (amethyst, citrine, smoky quartz, rock crystal) or diaspore, iolite and scapolite – can be evaluated and valued.
Which gemstones does the GLA evaluate?
You are welcome to have your faceted or mugel cut gemstone – a so-called “cabochon” – analyzed, diagnosed and valued in our gemmological laboratory. Please note that we only graduate cut gemstones and not rough gemstones or minerals. Australian opals are only evaluated on request. For the analysis and valuation of oriental pearls, jade, amber and turquoise, further mineralogical examinations may be necessary. Prior consultation with our experts is therefore essential.
How is the value of a gemstone determined?
The quality of a gemstone can be determined – based on the criteria for diamond grading – using the 4 Cs as follows:
- Carat (weight)
- Color (Color)
- Clarity (purity)
- Cut
These four characteristics together determine the value of a gemstone.For example, a large stone can have a significantly lower value if it has significant cracks and inclusions or if the cut is of inferior quality or has gone out of fashion. The color of a gemstone is determined by its saturation, intensity and vibrancy – the brilliance or play of color. For example, a stone with a hard shine that reflects light strongly is more valuable than a milky stone with little reflection.
What influences the value of gemstones?
Untreated gemstones of high quality are rare and are considered particularly valuable.
The following factors reduce the value of a gemstone:
- Cracks and inclusions
- Damage to the gemstone
- Artificial treatments such as crack filling, coating, heating, irradiation, impregnation, bleaching, etc.
For centuries, rubies and sapphires have often been artificially heated to intensify or change their color. The popularity of untreated gemstones has risen sharply in recent years. More and more gemmological gemstone appraisals are being requested in order to identify any defects and artificial enhancements that can no longer be diagnosed with a loupe alone.
GLA – Your partner for gemstone appraisals
We have been providing objective and independent expert opinions for diamonds and colored gemstones for over 40 years – the Gemmologisches Labor Austria with its generally sworn and court-certified expert MSt.in Adeline Lageder enjoys a high reputation in the industry.
This is how your gemstone appraisal is carried out:
The appraisal of gemstones and gemstone jewelry is a matter of trust.
We use our specially developed grading system to determine the value of faceted gemstones and gemstone jewelry. The weight and dimensions, color, purity, cut (type, shape, quality) as well as any treatments, damage and other value-reducing defects of the gemstone are scientifically examined using state-of-the-art technical laboratory equipment.
Depending on the purpose of the appraisal, you will receive a diagnostic and/or appraisal report that is recognized by courts, banks, insurance companies and gemstone dealers.
We will be happy to provide you with a free initial consultation.
Make an appointment for your gemstone appraisal now!