The spelling of Tibetan words in English is often misunderstood.

The "d" is not necessary, and is actually a modern substitute for "g." This introductory letter is never capitalized, unless other letters are capitalized. Thus:

gzi gZi GZI..., dzi dZi DZI..., zi. Zi ZI.

There is no such rendering as "Dzi." This is a mistake.

I have to suspect that your chung zi are derived from pieces of broken beads that have been recut. I would include your diagonal-striped bead as well.

JDA.