Or perhaps everything was not "stripped" from her until she went to Ekaterinburg. At Tobolsk they had a little more leeway.
The whole family continued to wear some items of jewelry until their latter days in the Ipatiev house, when their personal jewelry was collected and locked in a small box. This reportedly was a response to Nicholas' complaints of some pilfering of their personal effects by guards and service personnel who came to the house to clean, collect laundry,
etc. Nicholas received a receipt for the items collected, and the box was left on the premises until their deaths (although it was found empty, if I recall, by the White forces who took over the town shortly afterward).
As a matter of fact, if you look closely at the enlarged photo posted by Katherine, you'll notice that the daughter sitting to Alexandra's left is also wearing earrings.