Perhaps one week. Sometimes 10 - 14 days , depending on post office efficiency. The encryption system uses Javascript which is a client side process. In other words the encryption happens in your own web browser. This means that your credit details are encrypted before being sent.
Some secure sites do offer client side encryption.
No, we cannot guarantee that. Keep in mind though that opal is a very difficult stone to photograph. The colors leap back and forth, disappearing and reappearing. The pictures on the site do not give you a full picture of the stone. From some angles there is no color at all.