Can you please be more specific? I've posted a lot of things. I do try to post links to studies/papers wherever possible.amazingAkj|1432296687|3879995 said:Hey chrono, can you post pictures of whatever you have mention in your post so that it will be easy to recognize?
Abzurd|1432366364|3880357 said:Hi, I'm new to the world of coloured stones. During recent travels been exposed to tourmaline and emerald and decided I will learn and maybe create opportunity out of what has presented itself to me... Learnt a fair bit already in a short space of time...
Doesn't AIGS have better equiptment now for testing rubies and sapphires?Chrono|1437659749|3906462 said:Gem lab listing
USA
AGL is the top choice.
GIA is also good.
Europe
SSEF, Gubelin and GIA are the top choices.
Chris Dunaigre, GGTL and GRS are also good.
Asia
SSEF, Gubelin (mobile lab), Lotus Gemology and GIA are top choices.
For all else, as long as they aren't corundum (sapphire or ruby) which requires better equipment = AIGS, GIT, Burapha, Tokyo Gem Lab, Emil Gem Lab, Nanyang Gem Institute
Chrono|1437659749|3906462 said:Gem lab listing
USA
AGL is the top choice.
GIA is also good.
Europe
SSEF, Gubelin and GIA are the top choices.
Chris Dunaigre, GGTL and GRS are also good.
Asia
SSEF, Gubelin (mobile lab), Lotus Gemology and GIA are top choices.
For all else, as long as they aren't corundum (sapphire or ruby) which requires better equipment = AIGS, GIT, Burapha, Tokyo Gem Lab, Emil Gem Lab, Nanyang Gem Institute
Another big thank you from another newbie here. I used to shy away from purchasing colored stones, but now I feel a little more confident in taking the leap into the technicolor world. Thanks for the helpful information.onedrop|1337722177|3201140 said:LD: thank you for taking the time to write up all that valuable information! I am (was) clueless about colored stones, even though I've wanted one for years, but now after reading your write-up I feel so much better about making a good choice in the future!!
Do fake/synthetic/man made colored gemstones have any value at all? I mean is there expensive man made colored gemstone
The following came about from the following thread by Roger Dery with regards to what types of stones are best suited for rings.
[URL='https://www.pricescope.com/community/threads/lowest-mohs-hardness-for-rings-other-decisive-factors.176872/#post-3220969#p3220969']https://www.pricescope.com/community/threads/lowest-mohs-hardness-for-rings-other-decisive-factors.176872/#post-3220969#p3220969[/URL]
Mohs 9 - Ruby and Sapphire: generally considered the most durable of the colored gems. If untreated in any way, will hold up very well in most all situations. Even those subjected to 'high-heat-only' still do very well. Example: my wife's 2ct oval Sapphire engagement ring was worn daily for 15 years before needing a very minor tune-up. Exception: Ruby that has been filled with substances such as glass have a much lower resistance to damage such as abrasion from wear. Ruby, under high-heat-only with flux present, will also handle wear well.
Mohs 8-1/2 - Chrysoberyl including Alexandrite: in my experience Chrysoberyl holds up very well against wear. It does not exhibit severe brittleness seen in other gems - and would be a great stone for regular wear as a ring stone.
Mohs 8 - Spinel: is generally considered a gem that wears well. It is resistant to damage and not just damage from abrasion.
Mohs 8 - Topaz: can be worn in rings, but some caution should be exhibited. This is especially true with Topaz colored blue because it has been irradiated [and then subsequently heated]. This process has weakened the stone in some way that it does not hold up as well as Precious Topaz - which may, or may not have been treated at all.
Mohs 7-1/2-8 - the Beryl family including Aquamarine, Heliodore (golden Beryl), Morganite, Goshenite wear fairly well and unless totally exposed from the metal, can be worn in rings though may not be suitable for 'everyday wear'. The heating of any of the Beryl's is done at a low temperature and it is not a factor regarding their durability. Beryl's do have an element of brittleness though not as severe as some other gems.
Mohs 7-1/2-8 - Emerald (of the Beryl family) is not well suited for everyday wear. A totally clean Emerald will hold up as well as an Aquamarine. But, finding an Emerald with that level of clarity is extremely rare. Roughly 99% of all Emeralds have been treated with a filler of some type to (usually) improve their clarity. The filler is likely to not hold up well over time. *Emerald's that have been treated should not be placed into an Ultrasonic cleaner, nor placed under a steam cleaner as this may affect the clarity enhancement substance. **Caveat: Emerald's treated with a specialized process known as "Excell" in the trade are known to have a higher level of durability over those treated with other methods.
Mohs 7-1/2 - Andalusite has reasonable wearability though it does have a slight brittleness. Facet junctions are likely to show wear after only a few years regular wear. Distinct cleavage is present in Andalusite though I have yet to see the affects of it.
Mohs 7-1/2 - Iolite in my experience holds up fairly well for hardness 7-1/2. It does, however, have distinct cleavage and a sharp blow in one or more specific directions may cause it to separate into more than one piece. Though, when I have tried to do this in the rough, I have not been successful.
Mohs 7-7-1/2 - The Garnet group is generally thought of as reasonably durable. Facet junctions will show wear within the first few years of being worn. And, the facet junctions may not chip as much as 'crumble' for lack of a better way to describe this. Of the Garnets, the Andradite/Demantoid type is the least durable, and we have found the Pyrope/Almandine/Spessartite group seem to wear slightly better.
Mohs 7-7-1/2 - The Tourmaline group is suitable for rings, though not for everyday wear especially if the top of the stone is exposed. Tourmaline can be brittle, does not hold up well where temperature changes are radical. They are known to 'chippy' as can be seen along facet junctions that are exposed.
Mohs 6-1/2 to 7-1/2 - Zircon is often thought of as brittle. Zircons heated to high temperatures (over 1,000*C) to convert them to blue are definitely more brittle and show the effects of wear easily. Blue Zircon worn high on a mounting will need refurbishing regularly. Unheated Zircons and those subjected to much lower temperatures (of various colors) are less prone to show wear - and appear less brittle. There is no known dilemma with faceting or polishing Zircon for the experienced lapidary. There is, however, a known direction to its hardness which could create difficulty for some.
Mohs 7 - The Quartz family is well known due to being available and popular. Its wear pattern is predictable. Facet junctions (even when faceting) can be 'chippy'. Chipping along the crown facets is common, and abrasions from wear are as well.
*as a general rule, at least from me, I don't suggest wearing hardness less than 7 on a regular basis as the wear will become evident well before you expect it. I do suggest moving this type of gemstone into mountings offering great protection or off the fingers or wrist.
Mohs 6-1/2 to 7 - Kunzite is not a durable gemstone. It is brittle, does not resist scratching well, does not repair easily, and has perfect cleavage in two directions. In addition to all that, it has the unfortunate problem of being light sensitive - reducing its depth of color with prolonged exposure to direct sunlight. I have repaired my fair share of Kunzite's and I don't relish the fact that they show up waiting for my handy work. But since they don't wear well over time, they will all eventually need reconditioning.
Mohs 6-1/2 to 7 - Peridot does not share the fate of Kunzite, though its wear pattern is predictable. Abrasions are readily seen on exposed gems that are frequently worn - and fortunately, a refurbishing is not usually problematic.
Mohs 6-1/2 to 7 - Tanzanite is very popular and goldsmiths have taken to mounting them in lavish and risky ways. Exposed surfaces will show wear in a relatively short time and the perfect cleavage can be a problem. Tanzanite is also heat sensitive - even though it is well known to have been heated to acquire the beautiful blue to purple hues. It is the shock of rapid temperature change that may cause damage. This is not a common situation with consumers as this is more likely to take placec in the creation or repair to a mounting.
Mohs lower than 6-1/2 - Apatite, Opal, Orthoclase/Sunstone, Scapolite, Sphene and Sphalerite and other low hardness gems all need special care to be worn in rings. It is generally accepted that these gems are best suited for pendants, pins, brooches or earrings.