Sunnah.com reference : Book 7, Hadith 72English translation : Book 7, Hadith 841Arabic reference : Book 7, Hadith 838
Narrated Fadala bin 'Ubaid (RA):
I bought a necklace for twelve Dinars at the battle of Khaibar and it contained gold and gems. I considered them separately and found that it was worth more than twelve Dinars. I told the Prophet (ﷺ) about that and he said, "It must not be sold till the contents are considered separately."

[Reported by Muslim].
وَعَنْ فَضَالَةَ بْنِ عُبَيْدٍ ‏- رضى الله عنه ‏- قَالَ: { اِشْتَرَيْتُ يَوْمَ خَيْبَرَ قِلَادَةً بِاِثْنَيْ عَشَرَ دِينَاراً, فِيهَا ذَهَبٌ وَخَرَزٌ، فَفَصَلْتُهَا  1‏ فَوَجَدْتُ فِيهَا أَكْثَرَ مِنْ اِثْنَيْ عَشَرَ دِينَاراً, فَذَكَرْتُ ذَلِكَ لِلنَّبِيِّ ‏- صلى الله عليه وسلم ‏-فَقَالَ: " لَا تُبَاعُ حَتَّى تُفْصَلَ }  رَوَاهُ مُسْلِمٌ  2‏ .‏‏1 ‏- أي: جعلت الذهب وحده والخرز وحده.‏‏2 ‏- صحيح.‏ رواه مسلم ( 1591 )‏ ( 90 )‏.‏