SikhNet article "Adornment: Sohavi… So Beautiful"
http://www.sikhnet.com/news/adornment-sohavi-so-beautiful

In this You-tube video excerpt of a Yogi Bhajan lecture titled "Humbleness and Wearing Jewelry" published by Gurumustuk at SikhNet, Yogi Bhajan states that Sikhs should wear jewelry and Yogi Bhajan even goes further in the video to ridicule Singh's of the Khalsa panth who wear NO yogic rings or jewelry! Notice the huge gems Yogi Bhajan is wearing in the video. https://www.youtube.com/watch?v=MTxVqZ_9kuU&feature=player_embedded

Firstly, the symbol known as the Khanda or, if you are a Yogi Bhajan follower, the "Adi Shakti", did not come into general usage until the beginning of the 20th Century, so the jeweled khanda depicted in many SikhNet articles adorning Guru Gobind Singh Ji's forehead, is historically incorrect. https://www.facebook.com/photo.php?fbid=3347727331365&set=a.1932906121719.115469.1214270541&type=3&theater

Now to give a little perspective on this issue of jewelry in Sikhism:

Volume 5 of Macauliffe's The Sikhs, tells the life story of Guru Gobind Singh ji. On page 149 I found this footnote which I reproduce here:

"In the time of the Guru men who could afford the expense wore gold and silver ornaments. The Guru desired to wean his followers from the practice and counseled his followers to depend on steel, both for ornaments and defensive weapons."

So the justification by Yogi Bhajan that Guru Gobind Singh Ji loved to wear such jewelry is without merit as Guru Sahib Ji apparently "wanted his Sikhs to eschew such ostentatious displays of wealth."
http://www.gurmukhyoga.com/forum/index.php?id=441
http://forums.delphiforums.com/Kamallarose/messages?msg=1647.27

Now we all know that Guru Gobind Sinh Ji never practiced any tantric yoga & would never wear yogi gemstones so Yogi Bhajan's further justification for wearing tantric necklaces for power is also flatly repudiated. http://www.gurmukhyoga.com/forum/index.php?id=556

Let's see what Gurbani says about jewelry:

ਲਖ ਟਕਿਆ ਕੇ ਮੁੰਦੜੇ ਲਖ ਟਕਿਆ ਕੇ ਹਾਰ ॥.
They wear earrings, and necklaces worth thousands of dollars.

ਜਿਤੁ ਤਨਿ ਪਾਈਅਹਿ ਨਾਨਕਾ ਸੇ ਤਨ ਹੋਵਹਿ ਛਾਰ ॥.
Those bodies on which they are worn, O Nanak, those bodies turn to ashes.

ਆਸਾ ਕੀ ਵਾਰ: (ਮ: ੧) ਗੁਰੂ ਗ੍ਰੰਥ ਸਾਹਿਬ : ਅੰਗ ੪੬੪ ਪੰ. ੧੯
Raag Asa Guru Nanak Dev Ang:464 Line: 19.

I will also point out that the jeweler & author of this article justifies her adorning herself with jewelry by quoting Gurbani: "I have decorated myself to meet my Husband Lord."

To me Guru Sahib Ji is telling us to decorate ourselves by singing the name of God and is not talking about adorning ourselves with expensive material decorations.