Hi Salconia, excellent question and assuming i've understood correctly, there is a way to do this...
Create ID numbers & assign them
1) Start by numbering your physical collection
Label each specimen with a unique ID number. I would suggest using a 4 or 5 digit number format with leading zeroes. ie. #00123. Using leading zeroes is important.
2) Add your ID numbers to the crystal profile(s) in the app
Go to the relevant profile in the app and under the Personal Notes field, add a hashtag plus your matching specimens ID number, ie. #00123 (you can add as many different hash-tagged numbers as you need under each profile).
Find them later
3) Looking up a crystal using its ID number
Go to Search By Name, select 'Hash Tags Only' and enter your physical specimens number. Hitting search should locate it's corresponding crystal profile.
4) Finding physical specimens that match the crystal profile you're browsing
The profile's Personal Notes section will display the specimen ID numbers that you assigned earlier (in step 2), making them easy to locate in your real collection. Just find the matching number(s) in your real collection.