With respect, Caesium has not been a driver for WR1's (Winsome)...

With respect, Caesium has not been a driver for WR1's (Winsome) share price. Their run up to over $2 was based on Canadian lithium discoveries, in particular the JORC resource of 77.9Mt @ 1.15% re Adina with the price then coming off with the general decline in lithium prices.

On the 3rd April 2024 WR1 announced an option to buy a still fairly new DMS processing facility previously used for diamonds (the Renard plant) that is about 60km via an as yet unconstructed road from their Adina deposit. This caused the second run-up in their price into the $1.40's and they have come back off that peak to ~60c. It remains unknown whether TG6, CHR or possibly E25 may have a discovery and look to replicate the buy/convert old plant strategy as at least two companies have explored using Poisedon's Lake Johnston flotation nickel plant and converting it to lithium.

You possibly meant WA1 which is the well known example re Niobium however their ore is a carbonatite containing Niobium. Their met test work update of 26 June confirms that they recover key Niobium containing minerals of pyrochlore and columbite (again not Caesium).

Caesium (Cs) one of the pathfinder elements that is sometimes found in elevated levels near lithium deposits. I'm not aware of any lithium deposit having been found directly from elevated Cs readings but its theoretically possible. Cs itself is a fairly low demand mineral with world sales US$340m/yr but demand growth is forecast.

Sinclair in the goldfields and near the Pioneer Dome lithium deposit was Australia's first Caesium deposit but it was quickly mined out. Sinclair and Pioneer Dome were owned by Essential Metals, and then rolled into Develop Global.