I have a permanent residency in Canada. I want to bring 3 pieces of diamond jewelry with me when I move costing 3000, 7000 and 11000 Canadian dollar. How much duty will I have to pay?
According to the Canadian border services agency, the duties and taxes can vary a bit. In particular, in addition to any duties you may also need to pay appropriate sales tax etc for your province or residence.
As this can be complex, they also provide a calculator to estimate this: https://www.cbsa-asfc.gc.ca/travel-voyage/dte-acl/est-cal-eng.html
Currently (4th january 2019) this provides a tax estimate of $2924.25 for the details you have given.
If this is your first trip to Canada as part of your settlement, that is, starting a household, your personal, household goods can be imported (mostly) free from duty and taxes. The information is here.
The information specific to jewelry includes:
Describe each item of jewellery you plan to bring into Canada on the list of goods you submit. Since jewellery is difficult to describe accurately, it is best to use the wording from your insurance policy or jeweller's appraisal and to include photographs that have been dated and signed by jeweller or gemologist. This makes it easier to identify the jewellery when you first enter Canada, and later when you return from abroad with the jewellery.
You have to fill out a complete list of the household goods that you're bringing in with you or that will follow later.