Healing Properties for Black Obsidian?

An obsidian alien head

Talk about a conflict of interest here, I've been reading Graham Hancock's novel 'War God: Nights of the Witch', where Graham writes about how the Aztecs used obsidian knives to cut the hearts out of humans who were being sacrificed to the Aztec god.

Obsidian is a glass like volcanic rock which produces very sharp edges when split or cut the right way.

Then when I was looking up on the net about obsidian, I found this article about the -

Healing properties for Black Obsidian

"In crystal healing Black Obsidian is seen as providing an instant connection to the Root Chakra, it is a deeply grounding and protecting stone, defending the carrier from psychic attack.
It is also known as the “grief stone” as it is thought to be very helpful for those dealing with the loss of a loved one.

If it is held during meditation, it can unblock hidden feelings of grief allowing the healing process to start."

That link was also where I found the obsidian angels (of death?!) and the alien head pictured up the top of this post.

Heads DID roll: The blood and hair that proves Mexicans used stone knives for human sacrifice 1,000 years before Aztecs
"Muscle, tendons, skin and hair on a sharp obsidian knife from 2,000 years ago have proved that the stone weapon was used for human sacrifices.
The forensic samples prove that brutal human sacrifices were being carried out in the region 1,000 years BEFORE the Aztecs.
Mexico's National Institute of Anthropology and History said the finding clearly corroborates accounts from later cultures about the use of sharp obsidian knives in sacrificing humans."

So, the healing properties of obsidian really does seem to be very much a double-edged knife when it comes to the subject of healing and harm.

I was listening to this interesting podcast a few weeks back and remembered that obsidian was mentioned as one of the seven archetypal stones by Nicholas Pearson.
You can hear part two of the podcast here.

I thought it was interesting that when I was reading Tracey Rollin's book about Santa Muerte how Tracey mentions the Mexican/Aztec beliefs and the Spanish/Catholic beliefs have been synchretized into the Day of the Dead celebrations we see held in Mexico every year in November.
Santa Muerte: Our Lady of the Holy Death?

Graham Hancock in his 'War God' novel mentions that the Aztecs also practiced ritual cannibalism like cooking and eating the thigh meat of victims, which abhorred the Spanish invaders.

Which made me wonder about some of the Halloween lollies I bought this year, which were gummy body parts, like brains, feet, teeth(?!) and noses.
I know that zombies are meant to eat body parts like brains and entrails to stay alive, but it made me think also of the practice of cannibalism among the Aztecs and the Day of the Dead and Halloween occurring around the same time of the year and whether this is just another example of synchretism.  

I guess there are many ways of looking at the subject of obsidian and its hidden properties and uses?
And not all of them are good it seems.

Angel of death?