Iridium chloride when in a larger glass or plastic container is brownish, but when in smaller quantities such as the pipette below it is yellow with a slight brown tint.

12x – Iridium chloride (1ml of this chloride solution = 1mg of 99.99% pure Iridium) in neck of a polypropylene pipette that will disperse drops onto glass slides to conduct this series of microchems.

10x – a couple drops of Iridium chloride on glass slide, further indicating color against a white background. The black specs are extraneous particles adhering to the paper napkin under the glass slide.

10x – The previous 2 drops of Iridium chloride that is almost dry by using cigarette lighter flame to underside of glass slide.
The odor from the vapors emanating from the drying process somewhat resembles burnt bread.
When the solution is thoroughly dry it slowly absorbs (hydroscopic) moisture from the air.

10x – Two crystals of K2Cr2O7 inserted into 2 drops of Iridium Chloride.
The potassium dichromate is slowly dissolving creating the reddish appearance.
Because there were no precipitants formed heat was applied to see what, if any reaction would occur, which the next image illustrates..

30x – When heat from cigarette lighter flame was applied to underside of glass slide it did not take long for a rather microscopic size violent reaction to occur, which was manifested with considerable bubbling along the perimeter of solution.
The heat also caused a precipitation to occur (tiny dark colored particles).

10x – This image illustrates the results of the gently applied heat that dried this solution of K2Cr2O7 and Iridium chloride.
Because potassium dichromate failed to indicate a precipitant when at ambient temperature I would not consider this reagent to be an acceptable agent in determining the presence of Iridium in a chloride solution. Having said this, this microchem might have some bearing on a similar test which has unknown elements.

The next 4 images using the reagent Potassium Iodide is about the same limited value as the K2Cr2O7.

10x – Two KI crystals were inserted into 2 drops of Iridium chloride solution and no precipitants formed, so a little heat was applied to see if heat would cause a precipitant to occur.
The gently applied heat to underside of glass slide caused this perimeter of semi-dry supersaturated formation.

10x – This image of the same solution as previous image is due to a little more applied heat.

10x – Same image as preceding, but the residual heat of the glass slide slowly finished drying the Ir and KI solution.

40x – A magnified view of the top portion of the previous image.
In my opinion KI is of no practical value in determining Ir in a chloride solution, unless Ir is the only element present. This determination is due primarily because no specific identifiable precipitation occurred.

10x – A couple crystals of ammonium chloride was inserted into 2 drops of Iridium chloride.
No immediate precipitation occurred, so a little bit of heat was applied to the underside of glass slide.
The above crystalline formation began to appear as the solution became super saturated.

50x – When the ammonium chloride and Iridium chloride solution began to dry these tiny dark crystals began forming and littered the whole solution area.
There is also a slight pink in the white crystalline areas.

70x – A magnified view of the preceding image that provides better definition of the precipitation that ammonium chloride and a little heat caused.
Obviously, ammonium chloride is a reagent to use in identifying Iridium in a chloride solution. Further tests would need to be conducted to verify if ammonium chloride will precipitate Iridium that may be contaminated with other possibly interfering elements.

10x – Oxalic acid was added to 1 drop of Iridium chloride. No identifiable precipitant formed. So, this is not a reagent to use in determining the presence of Iridium in a chloride solution.

Note: Despite the reality that Oxalic acid and stannous chloride do not create reliable Ir precipitations they nonetheless were employed and shown here so the prospector can have an idea of what to expect.

10x – Stannous chloride was added to a drop of Iridium Chloride to see if a precipitant would form. No precipitant formed, so this is not a reagent to use in determining the presence of Iridium in a chloride solution.

50x – To two drops of Iridium Chloride powdered zinc metal was added. When the cementation process was complete this toothpick was inserted to mop-up the resultant Ir cemented zinc shown in this image.

The next image is of a portion of this toothpick tip that was ignited.

70x – This photomicrograph of a portion of the toothpick tip in previous image is focused on a tiny particles of reduced metal that is likely both Zn and Ir.

70x – This image is of a toothpick tip that was dipped in the Iridium chloride solution and ignited. Lower magnification does not show the metal that this magnification barely accomplishes (shiny areas). I am surprised that any metal shows because of the high temperature required. There is more reduced metal but could not focus in on all at same time.