I think it's the 'Assembled' terminology that is confusing people.
Once upon a time, 'Assembled' across the Gemporia group was aimed at doublet or triplet cabochons. Stones that were placed on a backing and had a Quartz cab over the top. Stones such as 'Mosaic Opal' or 'Crystal Opal on Ironstone'.
These days, they seem to use 'Assembled' for anything that involves some sort of 'manual' process or a method that doesn't fit under any of their other treatment codes. For example, they list the treatment for Lehrer's 'Cosmic Obelisk' stones as 'Assembled' too - but the stones are 'normal' / untreated - they've just been joined together to create the obelisk shape and effect.
Their treatment codes could do with a refresh because they're out of date and get confused even between presenters.
They often use (CP) for compressed and (RE) for reconstituted - even though they are both the same thing. Their website tells us what (RE) is - but the last time I looked, (CP) was not listed on their website at all. (CP) is not, and was never, needed. (RE) covered it already.
They use (H) for heat treatment and (IR) for irradiation - but for the past four years or so, they've added an (IH) - which presumably means irradiated AND heat treated - but, again. the last time I looked, (IH) was not listed on their website.
Some of their treatments are also so aggressive, they could do with a new treatment listed - to the point where 'rebuilt' would be a fair description.
Add to the above, Jewellery Maker throw in more confusion because they list the wrong treatment codes completely - despite me raising it with them, literally, for about the past 6 years. As always, I get the standard response of "we'll raise it with the team" - only for nothing to change. Basically, JM keep listing irradiated stones as (I) instead of (IR) - and they list diffused stones as (D) instead of (U).
(D) is actually for dyed stones - and (U) is for diffused.
Even their own presenters get confused by it. A few years ago, Rebecca Redican was flogging some Turquoise with the treatment code (IR) and she said, I quote, 'This stone has been irradiated - irradiation treatment is what gives the stone its colour".
That was flawed for two reasons:
a) The code she was referring to (I) stood for waxing - so the stones had just a wax coating applied to give them their glossy appearance and to prevent body salts/sweat being absorbed into the porous stone. The colour was actually natural.
b) Turquoise is a porous stone. It cannot be irradiated. It will disintegrate.
It baffles me how a so called GIA-AJP qualified presenter could claim that irradiation would give Turquoise its colour. Even someone with very basic knowledge of gemstones would know that Turquoise cannot be irradiated.