There is something called "edible gold foil" and "edible silver foil" that is basically made of pure silver and gold which has been transferred into extremely thin foil which is edible. This is commonly used (very sparingly) as a decoration on the top of Indian and Pakistani sweets. Is it lawful to eat this?
Sheikh `Abd al-Rahmân b. Ibrâhîm al-`Uthmân, professor at al-Imâm University
It seems to me that edible gold or silver foil is something that would be unlawful, and Allah knows best. I say this in consideration of the fact that the Prophet (peace be upon him) prohibited us from eating with utensils made of gold or silver. How then could it be permitted for us to consume gold and silver?
Hudhayfah b. al-Yamân relates that Allah’s Messenger (peace be upon him) said: “Do not drink from gold and silver vessels and do not eat from gold and silver dishes, because indeed they are for them in this world and for you in the Hereafter.” [Sahîh al-Bukhârî and Sahîh Muslim]
Umm Salamah relates that the Prophet (peace be upon him) said: “A person who drinks or eats from a silver or golden dish merely swallows into his stomach the fire of Hell.” [Sahîh Muslim]
This all comes under the general category of squandering wealth, which is forbidden. Allah says: “But squander not (your wealth) in the manner of a spendthrift, verily spendthrifts are the brothers of devils, and Satan is to his Lord ungrateful.” [Sûrah al-Isrâ’: 26-27]
May Allah guide us all.
Source: Islam Today
-- Al Arabiya Digital