Very bizarre jade half-balance

[Dinkhart]

Below is a Sheaffer that was on eBay recently. This is one of the well-known (to Sheaffer collectors) "half-Balances", with a Balance style cap and a flat top barrel. But that's not what makes this pen exceptional: it bears the flattened ball clip and is jade. Jade was ostensibly discontinued in 1932, yet the clip here was introduced in late 1934 or 1935 according to Richard Binder's website. Hence we must conclude either that jade lasted at least into 1934, or that the flattened ball clip was introduced in 1932 or earlier. If we choose the former conclusion, we can gather that half-Balance lasted at least into the mid-1930s. Thoughts welcome!
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